Add a lab introducing USB drivers #1

dbaluta · 2017-07-14T13:38:51Z

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update_1

If we're using the default implementation of kgdb_roundup_cpus() that uses smp_call_function_single_async() we can end up hanging kgdb_roundup_cpus() if we try to round up a CPU that failed to round up before. Specifically smp_call_function_single_async() will try to wait on the csd lock for the CPU that we're trying to round up. If the previous round up never finished then that lock could still be held and we'll just sit there hanging. There's not a lot of use trying to round up a CPU that failed to round up before. Let's keep a flag that indicates whether the CPU started but didn't finish to round up before. If we see that flag set then we'll skip the next round up. In general we have a few goals here: - We never want to end up calling smp_call_function_single_async() when the csd is still locked. This is accomplished because flush_smp_call_function_queue() unlocks the csd _before_ invoking the callback. That means that when kgdb_nmicallback() runs we know for sure the the csd is no longer locked. Thus when we set "rounding_up = false" we know for sure that the csd is unlocked. - If there are no timeouts rounding up we should never skip a round up. NOTE #1: In general trying to continue running after failing to round up CPUs doesn't appear to be supported in the debugger. When I simulate this I find that kdb reports "Catastrophic error detected" when I try to continue. I can overrule and continue anyway, but it should be noted that we may be entering the land of dragons here. Possibly the "Catastrophic error detected" was added _because_ of the future failure to round up, but even so this is an area of the code that hasn't been strongly tested. NOTE #2: I did a bit of testing before and after this change. I introduced a 10 second hang in the kernel while holding a spinlock that I could invoke on a certain CPU with 'taskset -c 3 cat /sys/...". Before this change if I did: - Invoke hang - Enter debugger - g (which warns about Catastrophic error, g again to go anyway) - g - Enter debugger ...I'd hang the rest of the 10 seconds without getting a debugger prompt. After this change I end up in the debugger the 2nd time after only 1 second with the standard warning about 'Timed out waiting for secondary CPUs.' I'll also note that once the CPU finished waiting I could actually debug it (aka "btc" worked) I won't promise that everything works perfectly if the errant CPU comes back at just the wrong time (like as we're entering or exiting the debugger) but it certainly seems like an improvement. NOTE #3: setting 'kgdb_info[cpu].rounding_up = false' is in kgdb_nmicallback() instead of kgdb_call_nmi_hook() because some implementations override kgdb_call_nmi_hook(). It shouldn't hurt to have it in kgdb_nmicallback() in any case. NOTE #4: this logic is really only needed because there is no API call like "smp_try_call_function_single_async()" or "smp_csd_is_locked()". If such an API existed then we'd use it instead, but it seemed a bit much to add an API like this just for kgdb. Signed-off-by: Douglas Anderson <[email protected]> Acked-by: Daniel Thompson <[email protected]> Signed-off-by: Daniel Thompson <[email protected]>

if secmark rules fail to unpack a double free happens resulting in the following oops [ 1295.584074] audit: type=1400 audit(1549970525.256:51): apparmor="STATUS" info="failed to unpack profile secmark rules" error=-71 profile="unconfined" name="/root/test" pid=29882 comm="apparmor_parser" name="/root/test" offset=120 [ 1374.042334] ------------[ cut here ]------------ [ 1374.042336] kernel BUG at mm/slub.c:294! [ 1374.042404] invalid opcode: 0000 [#1] SMP PTI [ 1374.042436] CPU: 0 PID: 29921 Comm: apparmor_parser Not tainted 4.20.7-042007-generic #201902061234 [ 1374.042461] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 [ 1374.042489] RIP: 0010:kfree+0x164/0x180 [ 1374.042502] Code: 74 05 41 0f b6 72 51 4c 89 d7 e8 37 cd f8 ff eb 8b 41 b8 01 00 00 00 48 89 d9 48 89 da 4c 89 d6 e8 11 f6 ff ff e9 72 ff ff ff <0f> 0b 49 8b 42 08 a8 01 75 c2 0f 0b 48 8b 3d a9 f4 19 01 e9 c5 fe [ 1374.042552] RSP: 0018:ffffaf7b812d7b90 EFLAGS: 00010246 [ 1374.042568] RAX: ffff91e437679200 RBX: ffff91e437679200 RCX: ffff91e437679200 [ 1374.042589] RDX: 00000000000088b6 RSI: ffff91e43da27060 RDI: ffff91e43d401a80 [ 1374.042609] RBP: ffffaf7b812d7ba8 R08: 0000000000027080 R09: ffffffffa6627a6d [ 1374.042629] R10: ffffd3af41dd9e40 R11: ffff91e43a1740dc R12: ffff91e3f52e8000 [ 1374.042650] R13: ffffffffa6627a6d R14: ffffffffffffffb9 R15: 0000000000000001 [ 1374.042675] FS: 00007f928df77740(0000) GS:ffff91e43da00000(0000) knlGS:0000000000000000 [ 1374.042697] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1374.042714] CR2: 000055a0c3ab6b50 CR3: 0000000079ed8004 CR4: 0000000000360ef0 [ 1374.042737] Call Trace: [ 1374.042750] kzfree+0x2d/0x40 [ 1374.042763] aa_free_profile+0x12b/0x270 [ 1374.042776] unpack_profile+0xc1/0xf10 [ 1374.042790] aa_unpack+0x115/0x4e0 [ 1374.042802] aa_replace_profiles+0x8e/0xcc0 [ 1374.042817] ? kvmalloc_node+0x6d/0x80 [ 1374.042831] ? __check_object_size+0x166/0x192 [ 1374.042845] policy_update+0xcf/0x1b0 [ 1374.042858] profile_load+0x7d/0xa0 [ 1374.042871] __vfs_write+0x3a/0x190 [ 1374.042883] ? apparmor_file_permission+0x1a/0x20 [ 1374.042899] ? security_file_permission+0x31/0xc0 [ 1374.042918] ? _cond_resched+0x19/0x30 [ 1374.042931] vfs_write+0xab/0x1b0 [ 1374.042963] ksys_write+0x55/0xc0 [ 1374.043004] __x64_sys_write+0x1a/0x20 [ 1374.043046] do_syscall_64+0x5a/0x110 [ 1374.043087] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 9caafbe ("apparmor: Parse secmark policy") Reported-by: Alex Murray <[email protected]> Signed-off-by: John Johansen <[email protected]>

[ 3.707412] Unable to handle kernel NULL pointer dereference at virtual address 0000009c [ 3.714511] pgd = (ptrval) [ 3.722742] [0000009c] *pgd=00000000 [ 3.725238] Internal error: Oops: 5 [#1] PREEMPT SMP ARM [ 3.728968] Modules linked in: [ 3.734265] CPU: 3 PID: 112 Comm: kworker/3:2 Tainted: G W 5.0.0-rc7-00183-g06a1c31df9eb #4 [ 3.737142] Hardware name: Generic DT based system [ 3.746778] Workqueue: events deferred_probe_work_func [ 3.751542] PC is at msm_gem_map_vma+0x3c/0xac [ 3.756669] LR is at msm_gem_get_and_pin_iova+0xd8/0x134 [ 3.761086] pc : [<c07d3b7c>] lr : [<c07d14f8>] psr: 60000013 [ 3.766560] sp : ee297be8 ip : ed9ab1c0 fp : ed93b800 [ 3.772546] r10: ee35e180 r9 : 00000000 r8 : ee297c80 [ 3.777752] r7 : 00000000 r6 : 7c100000 r5 : 00000000 r4 : ee35e180 [ 3.782968] r3 : 00000001 r2 : 00000003 r1 : ee35e180 r0 : 00000000 [ 3.789562] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 3.796079] Control: 10c5787d Table: 2e3a806 DAC: 00000051 [ 3.803282] Process kworker/3:2 (pid: 112, stack limit = 0x(ptrval)) [ 3.809006] Stack: (0xee297be8 to 0xee298000) [ 3.815445] 7be0: 00000000 c1108c48 eda8c000 00000003 eda8c0fc c1108c48 [ 3.819715] 7c00: eda8c000 00000003 eda8c0fc c07d14f8 00000001 c07d1100 7c100000 00000000 [ 3.827873] 7c20: eda8c000 bb7ffb78 00000000 eda8c000 00000000 00000000 c0c8b1d4 ee3bfa00 [ 3.836037] 7c40: ee3b9800 c07d1684 00000000 c1108c48 ee0d7810 ee3b9800 c0c8b1d4 c07d222c [ 3.844193] 7c60: ee3bfd84 ee297c80 00000000 c0b1d5b0 ee3bfc40 c07dcfd8 ee3bfd84 ee297c80 [ 3.852357] 7c80: 0000006d ee3bfc40 ee0d7810 bb7ffb78 c0c8b1d4 00000000 ee3bfc40 c07ddb48 [ 3.860516] 7ca0: 00002004 c0eba384 ee3bfc40 c079eba0 ee3bd040 ee3b9800 00000001 ed93b800 [ 3.868673] 7cc0: ed9aa100 c07db7e8 ee3bf240 ed9a6500 00000001 ee3b9800 ee3bf2d4 c07a0a30 [ 3.876834] 7ce0: ed93b800 7d100000 c1108c48 ee0d7610 ee3b9800 ed93b800 c1108c48 00000000 [ 3.884991] 7d00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 3.893151] 7d20: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 bb7ffb78 [ 3.901310] 7d40: c12113c4 ed93b800 ee3b9800 c1108c48 ee9eec10 00000000 ed93b800 7d100000 [ 3.909472] 7d60: eff7b000 c07cf748 7d100000 00000000 c0e9a350 c0b1d5b0 c12113c4 c0961e40 [ 3.917633] 7d80: c12113c4 40000113 eeff4bec c0ebe004 00000019 c0b1d230 ee9eeda8 60000113 [ 3.925791] 7da0: ee35d300 ee9eeda8 c07ce260 bb7ffb78 c07ce260 ee35d2c 00000028 00000002 [ 3.933950] 7dc0: eeb76280 c118f884 ee0be640 c11c6128 c07ce260 c07ea4ac 00000000 c0962b48 [ 3.942108] 7de0: c118f868 00000001 c0ebbc98 ee35d2c 00000000 eeb76280 00000000 c118f87c [ 3.950270] 7e00: ee35d2c 00000000 c11c63e0 c118f694 00000019 c07ea5d0 ee0d7810 00000000 [ 3.958430] 7e20: c118f694 00000000 00000000 c07f2b0c c120f55c ee0d7810 c120f560 00000000 [ 3.966590] 7e40: 00000000 c07f08c4 c07f0e8c ee0d7810 c11ba3d0 ee0d7810 c118f694 c07f0e8c [ 3.974748] 7e60: c1108c48 00000001 c0ebc3cc c11c63f8 c11ba3d0 c07f0c08 00000001 c07f2f8c [ 3.982908] 7e80: c118f694 00000000 ee297ed4 c07f0e8c c1108c48 00000001 c0ebc3cc c11c63f8 [ 3.991068] 7ea0: c11ba3d0 c07ee8a0 c11ba3d0 ee82686c ee0baf38 bb7ffb78 ee0d7810 ee0d7810 [ 3.999227] 7ec0: c1108c48 ee0d7844 c118faac c07f05b0 ee0d7810 ee0d7810 00000001 bb7ffb78 [ 4.007389] 7ee0: ee0d7810 ee0d7810 c118fd18 c118faac c11c63e0 c07ef7d0 ee0d7810 c118fa90 [ 4.015548] 7f00: c118fa90 c07efd68 c118fac8 ee27fe00 eefd9c80 eefdcd00 00000000 c118facc [ 4.023708] 7f20: 00000000 c033c038 eefd9c80 eefd9c80 00000008 ee27fe00 ee27fe14 eefd9c80 [ 4.031866] 7f40: 00000008 c1103d00 eefd9c98 ee296000 eefd9c80 c033ce54 ee907eac c0b1d230 [ 4.040026] 7f60: ee907eac eea24440 ee285000 00000000 ee296000 ee27fe00 c033ce24 eea2445c [ 4.048188] 7f80: ee907eac c0341db0 00000000 ee285000 c0341c8c 00000000 00000000 00000000 [ 4.056346] 7fa0: 00000000 00000000 00000000 c03010e8 00000000 00000000 00000000 00000000 [ 4.064505] 7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 4.072665] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000 [ 4.080828] [<c07d3b7c>] (msm_gem_map_vma) from [<c07d14f8>] (msm_gem_get_and_pin_iova+0xd8/0x134) [ 4.088983] [<c07d14f8>] (msm_gem_get_and_pin_iova) from [<c07d1684>] (_msm_gem_kernel_new+0x38/0xac) [ 4.097839] [<c07d1684>] (_msm_gem_kernel_new) from [<c07d222c>] (msm_gem_kernel_new+0x24/0x2c) [ 4.107130] [<c07d222c>] (msm_gem_kernel_new) from [<c07dcfd8>] (dsi_tx_buf_alloc_6g+0x44/0x90) [ 4.115631] [<c07dcfd8>] (dsi_tx_buf_alloc_6g) from [<c07ddb48>] (msm_dsi_host_modeset_init+0x80/0x104) [ 4.124313] [<c07ddb48>] (msm_dsi_host_modeset_init) from [<c07db7e8>] (msm_dsi_modeset_init+0x34/0x1c0) [ 4.133691] [<c07db7e8>] (msm_dsi_modeset_init) from [<c07a0a30>] (mdp5_kms_init+0x764/0x7e0) [ 4.143409] [<c07a0a30>] (mdp5_kms_init) from [<c07cf748>] (msm_drm_bind+0x56c/0x740) [ 4.151824] [<c07cf748>] (msm_drm_bind) from [<c07ea4ac>] (try_to_bring_up_master+0x238/0x2b4) [ 4.159636] [<c07ea4ac>] (try_to_bring_up_master) from [<c07ea5d0>] (component_add+0xa8/0x170) [ 4.168146] [<c07ea5d0>] (component_add) from [<c07f2b0c>] (platform_drv_probe+0x48/0x9c) [ 4.176737] [<c07f2b0c>] (platform_drv_probe) from [<c07f08c4>] (really_probe+0x278/0x404) [ 4.184981] [<c07f08c4>] (really_probe) from [<c07f0c08>] (driver_probe_device+0x78/0x1c0) [ 4.193147] [<c07f0c08>] (driver_probe_device) from [<c07ee8a0>] (bus_for_each_drv+0x74/0xb8) [ 4.201389] [<c07ee8a0>] (bus_for_each_drv) from [<c07f05b0>] (__device_attach+0xd0/0x164) [ 4.209984] [<c07f05b0>] (__device_attach) from [<c07ef7d0>] (bus_probe_device+0x84/0x8c) [ 4.218143] [<c07ef7d0>] (bus_probe_device) from [<c07efd68>] (deferred_probe_work_func+0x48/0xc4) [ 4.226398] [<c07efd68>] (deferred_probe_work_func) from [<c033c038>] (process_one_work+0x204/0x574) [ 4.235254] [<c033c038>] (process_one_work) from [<c033ce54>] (worker_thread+0x30/0x560) [ 4.244534] [<c033ce54>] (worker_thread) from [<c0341db0>] (kthread+0x124/0x154) [ 4.252606] [<c0341db0>] (kthread) from [<c03010e8>] (ret_from_fork+0x14/0x2c) [ 4.259966] Exception stack(0xee297fb0 to 0xee297ff8) [ 4.266998] 7fa0: 00000000 00000000 00000000 00000000 [ 4.272143] 7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 4.280297] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000 [ 4.288451] Code: e5813080 1a000013 e3a03001 e5c4307c (e590009c) [ 4.294933] ---[ end trace 18729cc2bca2b4b3 ]--- Signed-off-by: Luca Weiss <[email protected]> Signed-off-by: Rob Clark <[email protected]>

The event queue offers a way for the device to report access faults from endpoints. It is implemented on virtqueue #1. Whenever the host needs to signal a fault, it fills one of the buffers offered by the guest and interrupts it. Tested-by: Bharat Bhushan <[email protected]> Tested-by: Eric Auger <[email protected]> Reviewed-by: Eric Auger <[email protected]> Signed-off-by: Jean-Philippe Brucker <[email protected]> Signed-off-by: Michael S. Tsirkin <[email protected]>

…barrier free_user() could be called in atomic context. This patch uses non-sleeping cleanup_srcu_struct_quiesced(). At this stage atomic refcount is zero, thus all read-sections should have been ended. Example: BUG: sleeping function called from invalid context at kernel/workqueue.c:2856 in_atomic(): 1, irqs_disabled(): 0, pid: 177, name: ksoftirqd/27 CPU: 27 PID: 177 Comm: ksoftirqd/27 Not tainted 4.19.25-3 #1 Hardware name: AIC 1S-HV26-08/MB-DPSB04-06, BIOS IVYBV060 10/21/2015 Call Trace: dump_stack+0x5c/0x7b ___might_sleep+0xec/0x110 __flush_work+0x48/0x1f0 ? try_to_del_timer_sync+0x4d/0x80 _cleanup_srcu_struct+0x104/0x140 free_user+0x18/0x30 [ipmi_msghandler] ipmi_free_recv_msg+0x3a/0x50 [ipmi_msghandler] deliver_response+0xbd/0xd0 [ipmi_msghandler] deliver_local_response+0xe/0x30 [ipmi_msghandler] handle_one_recv_msg+0x163/0xc80 [ipmi_msghandler] ? dequeue_entity+0xa0/0x960 handle_new_recv_msgs+0x15c/0x1f0 [ipmi_msghandler] tasklet_action_common.isra.22+0x103/0x120 __do_softirq+0xf8/0x2d7 run_ksoftirqd+0x26/0x50 smpboot_thread_fn+0x11d/0x1e0 kthread+0x103/0x140 ? sort_range+0x20/0x20 ? kthread_destroy_worker+0x40/0x40 ret_from_fork+0x1f/0x40 Fixes: 77f8269 ("ipmi: fix use-after-free of user->release_barrier.rda") Signed-off-by: Konstantin Khlebnikov <[email protected]> Cc: [email protected] # 4.18 Cc: Yang Yingliang <[email protected]> Cc: Corey Minyard <[email protected]> Message-Id: <155229854905.2133.15708039732382992559.stgit@buzz> Signed-off-by: Corey Minyard <[email protected]>

The db->lock is a raw spinlock and so the lock hold time is supposed to be short. This will not be the case when printk() is being involved in some of the critical sections. In order to avoid the long hold time, in case some messages need to be printed, all the debug_object_is_on_stack() and debug_print_object() calls are now moved out of those critical sections in the following functions. - __debug_object_init() - debug_object_activate() - debug_object_deactivate() - debug_object_destroy() - debug_object_free() - debug_object_active_state() - __debug_check_no_obj_freed() - check_results() Holding the db->lock while calling printk() may lead to deadlock if printk() somehow requires the allocation/freeing of debug object that happens to be in the same hash bucket or a circular lock dependency warning from lockdep as reported in https://lkml.kernel.org/r/20181211091154.GL23332@shao2-debian [ 87.209665] WARNING: possible circular locking dependency detected [ 87.210547] 4.20.0-rc4-00057-gc96cf92 #1 Tainted: G W [ 87.211449] ------------------------------------------------------ [ 87.212405] getty/519 is trying to acquire lock: [ 87.213074] (____ptrval____) (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0xb4/0x302 [ 87.214343] [ 87.214343] but task is already holding lock: [ 87.215174] (____ptrval____) (&port_lock_key){-.-.}, at: uart_shutdown+0x3a3/0x4e2 [ 87.216260] [ 87.216260] which lock already depends on the new lock. This patch was also found to be able to fix a boot hanging problem when the initramfs image was switched on after a debugobjects splat from the EFI code. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Waiman Long <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Yang Shi <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Sergey Senozhatsky <[email protected]> Cc: Dmitry Safonov <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]>

The removal of shuffle_store() in v10 of the patch series was prompted by the review feedback to convert page_alloc_shuffle() to __memint. I obviously booted a stale kernel build in my tests because shuffle_store() is indeed required: BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 #PF error: [INSTR] PGD 0 P4D 0 Oops: 0010 [#1] SMP PTI CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc1+ #2867 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20180531_142017-buildhw-08.phx2.fedoraproject.org-1.fc28 04/01/2014 RIP: 0010: (null) Code: Bad RIP value. RSP: 0000:ffffffff82603e78 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: cccccccccccccccd RDX: ffffffff8261d7c0 RSI: ffffffff8244c010 RDI: ffff88843ffe1aaa RBP: ffff88843ffe1aac R08: ffffffff83486978 R09: 0000000000000000 R10: ffffffff82603e80 R11: 0000000000000048 R12: ffff88843ffe1a97 R13: ffff88843ffe1aaa R14: ffffffff8244c010 R15: 000000000000016d FS: 0000000000000000(0000) GS:ffff88811be00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000002614000 CR4: 00000000000606b0 Call Trace: ? parse_args+0x170/0x360 ? set_init_arg+0x55/0x55 ? start_kernel+0x1d8/0x4c4 ? set_init_arg+0x55/0x55 ? secondary_startup_64+0xa4/0xb0 Reintroduce it and mark it __meminit. Given the sysfs attribute is not writable it will never be called after init. Link: http://lkml.kernel.org/r/154943713038.3858443.4125180191382062871.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Kees Cook <[email protected]> Cc: Keith Busch <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Robert Elliott <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]>

Fix below issue reported by Coverity, actually, don't need this condition check here, remove it. CID undefined (#1 of 1): Wrong operator used (CONSTANT_EXPRESSION_RESULT)operator_confusion: (16UL /* 1UL << 4 */) | (__u16)(__le16)tcd->csr is always 1/true regardless of the values of its operand. This occurs as the logical first operand of "&&". Signed-off-by: Robin Gong <[email protected]> Reviewed-by: Shengjiu Wang <[email protected]> (cherry picked from commit ab942110975cadcde57ab1110df03f526bd3fec5)

We should use irq disabled mode when read/write hda registers from thread context, as we need to hold the same bus->reg_lock in interrupt context hda_dsp_stream_interrupt(), otherwise, when we are holding the lock in hda_dsp_stream_hw_free() and the interrupt arrives, we will get deadlock in the interrupt handler. Error logs like this: [ 5.603606] CPU0 [ 5.603606] ---- [ 5.603607] lock(&(&bus->reg_lock)->rlock); [ 5.603608] <Interrupt> [ 5.603609] lock(&(&bus->reg_lock)->rlock); [ 5.603610] *** DEADLOCK *** [ 5.603611] 2 locks held by pulseaudio/2329: [ 5.603612] #0: 000000005fcf26c6 (&card->mutex/1){+.+.}, at: dpcm_fe_dai_hw_free+0x2b/0x110 [snd_soc_core] [ 5.603619] #1: 00000000ef369faf (&rtd->pcm_mutex){+.+.}, at: soc_pcm_hw_free+0x2e/0x1c0 [snd_soc_core] The fix is simple, let's switch to use spin_lock/unlock_irq(). Reported-by: Xun Zhang <[email protected]> Signed-off-by: Keyon Jie <[email protected]>

Commit 87fd125 ("nvme-rdma: remove redundant reference between ib_device and tagset") caused a kernel panic when disconnecting from an inaccessible controller (disconnect during re-connection). -- nvme nvme0: Removing ctrl: NQN "testnqn1" nvme_rdma: nvme_rdma_exit_request: hctx 0 queue_idx 1 BUG: unable to handle kernel paging request at 0000000080000228 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI ... Call Trace: blk_mq_exit_hctx+0x5c/0xf0 blk_mq_exit_queue+0xd4/0x100 blk_cleanup_queue+0x9a/0xc0 nvme_rdma_destroy_io_queues+0x52/0x60 [nvme_rdma] nvme_rdma_shutdown_ctrl+0x3e/0x80 [nvme_rdma] nvme_do_delete_ctrl+0x53/0x80 [nvme_core] nvme_sysfs_delete+0x45/0x60 [nvme_core] kernfs_fop_write+0x105/0x180 vfs_write+0xad/0x1a0 ksys_write+0x5a/0xd0 do_syscall_64+0x55/0x110 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fa215417154 -- The reason for this crash is accessing an already freed ib_device for performing dma_unmap during exit_request commands. The root cause for that is that during re-connection all the queues are destroyed and re-created (and the ib_device is reference counted by the queues and freed as well) but the tagset stays alive and all the DMA mappings (that we perform in init_request) kept in the request context. The original commit fixed a different bug that was introduced during bonding (aka nic teaming) tests that for some scenarios change the underlying ib_device and caused memory leakage and possible segmentation fault. This commit is a complementary commit that also changes the wrong DMA mappings that were saved in the request context and making the request sqe dma mappings dynamic with the command lifetime (i.e. mapped in .queue_rq and unmapped in .complete). It also fixes the above crash of accessing freed ib_device during destruction of the tagset. Fixes: 87fd125 ("nvme-rdma: remove redundant reference between ib_device and tagset") Reported-by: Jim Harris <[email protected]> Suggested-by: Sagi Grimberg <[email protected]> Tested-by: Jim Harris <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Signed-off-by: Max Gurtovoy <[email protected]> Signed-off-by: Sagi Grimberg <[email protected]>

In order to create an internal vport, internal_dev_create() is used and that calls register_netdevice() internally. If register_netdevice() fails, it calls dev->priv_destructor() to free private data of netdev. actually, a private data of this is a vport. Hence internal_dev_create() should not free and use a vport after failure of register_netdevice(). Test command ovs-dpctl add-dp bonding_masters Splat looks like: [ 1035.667767] kasan: GPF could be caused by NULL-ptr deref or user memory access [ 1035.675958] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI [ 1035.676916] CPU: 1 PID: 1028 Comm: ovs-vswitchd Tainted: G B 5.2.0-rc3+ linux-kernel-labs#240 [ 1035.676916] RIP: 0010:internal_dev_create+0x2e5/0x4e0 [openvswitch] [ 1035.676916] Code: 48 c1 ea 03 80 3c 02 00 0f 85 9f 01 00 00 4c 8b 23 48 b8 00 00 00 00 00 fc ff df 49 8d bc 24 60 05 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 86 01 00 00 49 8b bc 24 60 05 00 00 e8 e4 68 f4 [ 1035.713720] RSP: 0018:ffff88810dcb7578 EFLAGS: 00010206 [ 1035.713720] RAX: dffffc0000000000 RBX: ffff88810d13fe08 RCX: ffffffff84297704 [ 1035.713720] RDX: 00000000000000ac RSI: 0000000000000000 RDI: 0000000000000560 [ 1035.713720] RBP: 00000000ffffffef R08: fffffbfff0d3b881 R09: fffffbfff0d3b881 [ 1035.713720] R10: 0000000000000001 R11: fffffbfff0d3b880 R12: 0000000000000000 [ 1035.768776] R13: 0000607ee460b900 R14: ffff88810dcb7690 R15: ffff88810dcb7698 [ 1035.777709] FS: 00007f02095fc980(0000) GS:ffff88811b400000(0000) knlGS:0000000000000000 [ 1035.777709] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1035.777709] CR2: 00007ffdf01d2f28 CR3: 0000000108258000 CR4: 00000000001006e0 [ 1035.777709] Call Trace: [ 1035.777709] ovs_vport_add+0x267/0x4f0 [openvswitch] [ 1035.777709] new_vport+0x15/0x1e0 [openvswitch] [ 1035.777709] ovs_vport_cmd_new+0x567/0xd10 [openvswitch] [ 1035.777709] ? ovs_dp_cmd_dump+0x490/0x490 [openvswitch] [ 1035.777709] ? __kmalloc+0x131/0x2e0 [ 1035.777709] ? genl_family_rcv_msg+0xa54/0x1030 [ 1035.777709] genl_family_rcv_msg+0x63a/0x1030 [ 1035.777709] ? genl_unregister_family+0x630/0x630 [ 1035.841681] ? debug_show_all_locks+0x2d0/0x2d0 [ ... ] Fixes: cf124db ("net: Fix inconsistent teardown and release of private netdev state.") Signed-off-by: Taehee Yoo <[email protected]> Reviewed-by: Greg Rose <[email protected]> Signed-off-by: David S. Miller <[email protected]>

The qp priv rcd pointer doesn't match the context being used for verbs causing issues when 9B and kdeth packets are processed by different receive contexts and hence different CPUs. When running on different CPUs the following panic can occur: WARNING: CPU: 3 PID: 2584 at lib/list_debug.c:59 __list_del_entry+0xa1/0xd0 list_del corruption. prev->next should be ffff9a7ac31f7a30, but was ffff9a7c3bc89230 CPU: 3 PID: 2584 Comm: z_wr_iss Kdump: loaded Tainted: P OE ------------ 3.10.0-862.2.3.el7_lustre.x86_64 #1 Call Trace: <IRQ> [<ffffffffb7b0d78e>] dump_stack+0x19/0x1b [<ffffffffb74916d8>] __warn+0xd8/0x100 [<ffffffffb749175f>] warn_slowpath_fmt+0x5f/0x80 [<ffffffffb7768671>] __list_del_entry+0xa1/0xd0 [<ffffffffc0c7a945>] process_rcv_qp_work+0xb5/0x160 [hfi1] [<ffffffffc0c7bc2b>] handle_receive_interrupt_nodma_rtail+0x20b/0x2b0 [hfi1] [<ffffffffc0c70683>] receive_context_interrupt+0x23/0x40 [hfi1] [<ffffffffb7540a94>] __handle_irq_event_percpu+0x44/0x1c0 [<ffffffffb7540c42>] handle_irq_event_percpu+0x32/0x80 [<ffffffffb7540ccc>] handle_irq_event+0x3c/0x60 [<ffffffffb7543a1f>] handle_edge_irq+0x7f/0x150 [<ffffffffb742d504>] handle_irq+0xe4/0x1a0 [<ffffffffb7b23f7d>] do_IRQ+0x4d/0xf0 [<ffffffffb7b16362>] common_interrupt+0x162/0x162 <EOI> [<ffffffffb775a326>] ? memcpy+0x6/0x110 [<ffffffffc109210d>] ? abd_copy_from_buf_off_cb+0x1d/0x30 [zfs] [<ffffffffc10920f0>] ? abd_copy_to_buf_off_cb+0x30/0x30 [zfs] [<ffffffffc1093257>] abd_iterate_func+0x97/0x120 [zfs] [<ffffffffc10934d9>] abd_copy_from_buf_off+0x39/0x60 [zfs] [<ffffffffc109b828>] arc_write_ready+0x178/0x300 [zfs] [<ffffffffb7b11032>] ? mutex_lock+0x12/0x2f [<ffffffffb7b11032>] ? mutex_lock+0x12/0x2f [<ffffffffc1164d05>] zio_ready+0x65/0x3d0 [zfs] [<ffffffffc04d725e>] ? tsd_get_by_thread+0x2e/0x50 [spl] [<ffffffffc04d1318>] ? taskq_member+0x18/0x30 [spl] [<ffffffffc115ef22>] zio_execute+0xa2/0x100 [zfs] [<ffffffffc04d1d2c>] taskq_thread+0x2ac/0x4f0 [spl] [<ffffffffb74cee80>] ? wake_up_state+0x20/0x20 [<ffffffffc115ee80>] ? zio_taskq_member.isra.7.constprop.10+0x80/0x80 [zfs] [<ffffffffc04d1a80>] ? taskq_thread_spawn+0x60/0x60 [spl] [<ffffffffb74bae31>] kthread+0xd1/0xe0 [<ffffffffb74bad60>] ? insert_kthread_work+0x40/0x40 [<ffffffffb7b1f5f7>] ret_from_fork_nospec_begin+0x21/0x21 [<ffffffffb74bad60>] ? insert_kthread_work+0x40/0x40 Fix by reading the map entry in the same manner as the hardware so that the kdeth and verbs contexts match. Cc: <[email protected]> Fixes: 5190f05 ("IB/hfi1: Allow the driver to initialize QP priv struct") Reviewed-by: Kaike Wan <[email protected]> Signed-off-by: Mike Marciniszyn <[email protected]> Signed-off-by: Dennis Dalessandro <[email protected]> Signed-off-by: Jason Gunthorpe <[email protected]>

Booting with kernel parameter "rdt=cmt,mbmtotal,memlocal,l3cat,mba" and executing "mount -t resctrl resctrl -o mba_MBps /sys/fs/resctrl" results in a NULL pointer dereference on systems which do not have local MBM support enabled.. BUG: kernel NULL pointer dereference, address: 0000000000000020 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 722 Comm: kworker/0:3 Not tainted 5.2.0-0.rc3.git0.1.el7_UNSUPPORTED.x86_64 #2 Workqueue: events mbm_handle_overflow RIP: 0010:mbm_handle_overflow+0x150/0x2b0 Only enter the bandwith update loop if the system has local MBM enabled. Fixes: de73f38 ("x86/intel_rdt/mba_sc: Feedback loop to dynamically update mem bandwidth") Signed-off-by: Prarit Bhargava <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: Fenghua Yu <[email protected]> Cc: Reinette Chatre <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: [email protected] Link: https://lkml.kernel.org/r/[email protected]

If a task is removing the block group that currently has the highest start offset amongst all existing block groups, there is a short time window where it races with a concurrent block group allocation, resulting in a transaction abort with an error code of EEXIST. The following diagram explains the race in detail: Task A Task B btrfs_remove_block_group(bg offset X) remove_extent_mapping(em offset X) -> removes extent map X from the tree of extent maps (fs_info->mapping_tree), so the next call to find_next_chunk() will return offset X btrfs_alloc_chunk() find_next_chunk() --> returns offset X __btrfs_alloc_chunk(offset X) btrfs_make_block_group() btrfs_create_block_group_cache() --> creates btrfs_block_group_cache object with a key corresponding to the block group item in the extent, the key is: (offset X, BTRFS_BLOCK_GROUP_ITEM_KEY, 1G) --> adds the btrfs_block_group_cache object to the list new_bgs of the transaction handle btrfs_end_transaction(trans handle) __btrfs_end_transaction() btrfs_create_pending_block_groups() --> sees the new btrfs_block_group_cache in the new_bgs list of the transaction handle --> its call to btrfs_insert_item() fails with -EEXIST when attempting to insert the block group item key (offset X, BTRFS_BLOCK_GROUP_ITEM_KEY, 1G) because task A has not removed that key yet --> aborts the running transaction with error -EEXIST btrfs_del_item() -> removes the block group's key from the extent tree, key is (offset X, BTRFS_BLOCK_GROUP_ITEM_KEY, 1G) A sample transaction abort trace: [78912.403537] ------------[ cut here ]------------ [78912.403811] BTRFS: Transaction aborted (error -17) [78912.404082] WARNING: CPU: 2 PID: 20465 at fs/btrfs/extent-tree.c:10551 btrfs_create_pending_block_groups+0x196/0x250 [btrfs] (...) [78912.405642] CPU: 2 PID: 20465 Comm: btrfs Tainted: G W 5.0.0-btrfs-next-46 #1 [78912.405941] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014 [78912.406586] RIP: 0010:btrfs_create_pending_block_groups+0x196/0x250 [btrfs] (...) [78912.407636] RSP: 0018:ffff9d3d4b7e3b08 EFLAGS: 00010282 [78912.407997] RAX: 0000000000000000 RBX: ffff90959a3796f0 RCX: 0000000000000006 [78912.408369] RDX: 0000000000000007 RSI: 0000000000000001 RDI: ffff909636b16860 [78912.408746] RBP: ffff909626758a58 R08: 0000000000000000 R09: 0000000000000000 [78912.409144] R10: ffff9095ff462400 R11: 0000000000000000 R12: ffff90959a379588 [78912.409521] R13: ffff909626758ab0 R14: ffff9095036c0000 R15: ffff9095299e1158 [78912.409899] FS: 00007f387f16f700(0000) GS:ffff909636b00000(0000) knlGS:0000000000000000 [78912.410285] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [78912.410673] CR2: 00007f429fc87cbc CR3: 000000014440a004 CR4: 00000000003606e0 [78912.411095] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [78912.411496] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [78912.411898] Call Trace: [78912.412318] __btrfs_end_transaction+0x5b/0x1c0 [btrfs] [78912.412746] btrfs_inc_block_group_ro+0xcf/0x160 [btrfs] [78912.413179] scrub_enumerate_chunks+0x188/0x5b0 [btrfs] [78912.413622] ? __mutex_unlock_slowpath+0x100/0x2a0 [78912.414078] btrfs_scrub_dev+0x2ef/0x720 [btrfs] [78912.414535] ? __sb_start_write+0xd4/0x1c0 [78912.414963] ? mnt_want_write_file+0x24/0x50 [78912.415403] btrfs_ioctl+0x17fb/0x3120 [btrfs] [78912.415832] ? lock_acquire+0xa6/0x190 [78912.416256] ? do_vfs_ioctl+0xa2/0x6f0 [78912.416685] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs] [78912.417116] do_vfs_ioctl+0xa2/0x6f0 [78912.417534] ? __fget+0x113/0x200 [78912.417954] ksys_ioctl+0x70/0x80 [78912.418369] __x64_sys_ioctl+0x16/0x20 [78912.418812] do_syscall_64+0x60/0x1b0 [78912.419231] entry_SYSCALL_64_after_hwframe+0x49/0xbe [78912.419644] RIP: 0033:0x7f3880252dd7 (...) [78912.420957] RSP: 002b:00007f387f16ed68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [78912.421426] RAX: ffffffffffffffda RBX: 000055f5becc1df0 RCX: 00007f3880252dd7 [78912.421889] RDX: 000055f5becc1df0 RSI: 00000000c400941b RDI: 0000000000000003 [78912.422354] RBP: 0000000000000000 R08: 00007f387f16f700 R09: 0000000000000000 [78912.422790] R10: 00007f387f16f700 R11: 0000000000000246 R12: 0000000000000000 [78912.423202] R13: 00007ffda49c266f R14: 0000000000000000 R15: 00007f388145e040 [78912.425505] ---[ end trace eb9bfe7c426fc4d3 ]--- Fix this by calling remove_extent_mapping(), at btrfs_remove_block_group(), only at the very end, after removing the block group item key from the extent tree (and removing the free space tree entry if we are using the free space tree feature). Fixes: 0421682 ("Btrfs: fix race between fs trimming and block group remove/allocation") CC: [email protected] # 4.4+ Signed-off-by: Filipe Manana <[email protected]> Signed-off-by: David Sterba <[email protected]>

Ido Schimmel says: ==================== mlxsw: Various fixes This patchset contains various fixes for mlxsw. Patch #1 fixes an hash polarization problem when a nexthop device is a LAG device. This is caused by the fact that the same seed is used for the LAG and ECMP hash functions. Patch #2 fixes an issue in which the driver fails to refresh a nexthop neighbour after it becomes dead. This prevents the nexthop from ever being written to the adjacency table and used to forward traffic. Patch Patch #4 fixes a wrong extraction of TOS value in flower offload code. Patch #5 is a test case. Patch #6 works around a buffer issue in Spectrum-2 by reducing the default sizes of the shared buffer pools. Patch linux-kernel-labs#7 prevents prio-tagged packets from entering the switch when PVID is removed from the bridge port. Please consider patches #2, #4 and #6 for 5.1.y ==================== Signed-off-by: David S. Miller <[email protected]>

There was the below bug report from Wu Fangsuo. On the CMA allocation path, isolate_migratepages_range() could isolate unevictable LRU pages and reclaim_clean_page_from_list() can try to reclaim them if they are clean file-backed pages. page:ffffffbf02f33b40 count:86 mapcount:84 mapping:ffffffc08fa7a810 index:0x24 flags: 0x19040c(referenced|uptodate|arch_1|mappedtodisk|unevictable|mlocked) raw: 000000000019040c ffffffc08fa7a810 0000000000000024 0000005600000053 raw: ffffffc009b05b20 ffffffc009b05b20 0000000000000000 ffffffc09bf3ee80 page dumped because: VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page)) page->mem_cgroup:ffffffc09bf3ee80 ------------[ cut here ]------------ kernel BUG at /home/build/farmland/adroid9.0/kernel/linux/mm/vmscan.c:1350! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 7125 Comm: syz-executor Tainted: G S 4.14.81 #3 Hardware name: ASR AQUILAC EVB (DT) task: ffffffc00a54cd00 task.stack: ffffffc009b00000 PC is at shrink_page_list+0x1998/0x3240 LR is at shrink_page_list+0x1998/0x3240 pc : [<ffffff90083a2158>] lr : [<ffffff90083a2158>] pstate: 60400045 sp : ffffffc009b05940 .. shrink_page_list+0x1998/0x3240 reclaim_clean_pages_from_list+0x3c0/0x4f0 alloc_contig_range+0x3bc/0x650 cma_alloc+0x214/0x668 ion_cma_allocate+0x98/0x1d8 ion_alloc+0x200/0x7e0 ion_ioctl+0x18c/0x378 do_vfs_ioctl+0x17c/0x1780 SyS_ioctl+0xac/0xc0 Wu found it's due to commit ad6b670 ("mm: remove SWAP_MLOCK in ttu"). Before that, unevictable pages go to cull_mlocked so that we can't reach the VM_BUG_ON_PAGE line. To fix the issue, this patch filters out unevictable LRU pages from the reclaim_clean_pages_from_list in CMA. Link: http://lkml.kernel.org/r/[email protected] Fixes: ad6b670 ("mm: remove SWAP_MLOCK in ttu") Signed-off-by: Minchan Kim <[email protected]> Reported-by: Wu Fangsuo <[email protected]> Debugged-by: Wu Fangsuo <[email protected]> Tested-by: Wu Fangsuo <[email protected]> Reviewed-by: Andrew Morton <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Pankaj Suryawanshi <[email protected]> Cc: <[email protected]> [4.12+] Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

Just like the case of commit 8b05a3a ("tracing/kprobes: Fix NULL pointer dereference in trace_kprobe_create()"), writing an incorrectly formatted string to uprobe_events can trigger NULL pointer dereference. Reporeducer: # echo r > /sys/kernel/debug/tracing/uprobe_events dmesg: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 8000000079d12067 P4D 8000000079d12067 PUD 7b7ab067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 1903 Comm: bash Not tainted 5.2.0-rc3+ linux-kernel-labs#15 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-2.fc30 04/01/2014 RIP: 0010:strchr+0x0/0x30 Code: c0 eb 0d 84 c9 74 18 48 83 c0 01 48 39 d0 74 0f 0f b6 0c 07 3a 0c 06 74 ea 19 c0 83 c8 01 c3 31 c0 c3 0f 1f 84 00 00 00 00 00 <0f> b6 07 89 f2 40 38 f0 75 0e eb 13 0f b6 47 01 48 83 c RSP: 0018:ffffb55fc0403d10 EFLAGS: 00010293 RAX: ffff993ffb793400 RBX: 0000000000000000 RCX: ffffffffa4852625 RDX: 0000000000000000 RSI: 000000000000002f RDI: 0000000000000000 RBP: ffffb55fc0403dd0 R08: ffff993ffb793400 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff993ff9cc1668 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f30c5147700(0000) GS:ffff993ffda00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000007b628000 CR4: 00000000000006f0 Call Trace: trace_uprobe_create+0xe6/0xb10 ? __kmalloc_track_caller+0xe6/0x1c0 ? __kmalloc+0xf0/0x1d0 ? trace_uprobe_create+0xb10/0xb10 create_or_delete_trace_uprobe+0x35/0x90 ? trace_uprobe_create+0xb10/0xb10 trace_run_command+0x9c/0xb0 trace_parse_run_command+0xf9/0x1eb ? probes_open+0x80/0x80 __vfs_write+0x43/0x90 vfs_write+0x14a/0x2a0 ksys_write+0xa2/0x170 do_syscall_64+0x7f/0x200 entry_SYSCALL_64_after_hwframe+0x49/0xbe Link: http://lkml.kernel.org/r/[email protected] Cc: [email protected] Fixes: 0597c49 ("tracing/uprobes: Use dyn_event framework for uprobe events") Reviewed-by: Srikar Dronamraju <[email protected]> Signed-off-by: Eiichi Tsukata <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>

It's possible for livepatch and ftrace to be toggling a module's text permissions at the same time, resulting in the following panic: BUG: unable to handle page fault for address: ffffffffc005b1d9 #PF: supervisor write access in kernel mode #PF: error_code(0x0003) - permissions violation PGD 3ea0c067 P4D 3ea0c067 PUD 3ea0e067 PMD 3cc13067 PTE 3b8a1061 Oops: 0003 [#1] PREEMPT SMP PTI CPU: 1 PID: 453 Comm: insmod Tainted: G O K 5.2.0-rc1-a188339ca5 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014 RIP: 0010:apply_relocate_add+0xbe/0x14c Code: fa 0b 74 21 48 83 fa 18 74 38 48 83 fa 0a 75 40 eb 08 48 83 38 00 74 33 eb 53 83 38 00 75 4e 89 08 89 c8 eb 0a 83 38 00 75 43 <89> 08 48 63 c1 48 39 c8 74 2e eb 48 83 38 00 75 32 48 29 c1 89 08 RSP: 0018:ffffb223c00dbb10 EFLAGS: 00010246 RAX: ffffffffc005b1d9 RBX: 0000000000000000 RCX: ffffffff8b200060 RDX: 000000000000000b RSI: 0000004b0000000b RDI: ffff96bdfcd33000 RBP: ffffb223c00dbb38 R08: ffffffffc005d040 R09: ffffffffc005c1f0 R10: ffff96bdfcd33c40 R11: ffff96bdfcd33b80 R12: 0000000000000018 R13: ffffffffc005c1f0 R14: ffffffffc005e708 R15: ffffffff8b2fbc74 FS: 00007f5f447beba8(0000) GS:ffff96bdff900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffc005b1d9 CR3: 000000003cedc002 CR4: 0000000000360ea0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: klp_init_object_loaded+0x10f/0x219 ? preempt_latency_start+0x21/0x57 klp_enable_patch+0x662/0x809 ? virt_to_head_page+0x3a/0x3c ? kfree+0x8c/0x126 patch_init+0x2ed/0x1000 [livepatch_test02] ? 0xffffffffc0060000 do_one_initcall+0x9f/0x1c5 ? kmem_cache_alloc_trace+0xc4/0xd4 ? do_init_module+0x27/0x210 do_init_module+0x5f/0x210 load_module+0x1c41/0x2290 ? fsnotify_path+0x3b/0x42 ? strstarts+0x2b/0x2b ? kernel_read+0x58/0x65 __do_sys_finit_module+0x9f/0xc3 ? __do_sys_finit_module+0x9f/0xc3 __x64_sys_finit_module+0x1a/0x1c do_syscall_64+0x52/0x61 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The above panic occurs when loading two modules at the same time with ftrace enabled, where at least one of the modules is a livepatch module: CPU0 CPU1 klp_enable_patch() klp_init_object_loaded() module_disable_ro() ftrace_module_enable() ftrace_arch_code_modify_post_process() set_all_modules_text_ro() klp_write_object_relocations() apply_relocate_add() *patches read-only code* - BOOM A similar race exists when toggling ftrace while loading a livepatch module. Fix it by ensuring that the livepatch and ftrace code patching operations -- and their respective permissions changes -- are protected by the text_mutex. Link: http://lkml.kernel.org/r/ab43d56ab909469ac5d2520c5d944ad6d4abd476.1560474114.git.jpoimboe@redhat.com Reported-by: Johannes Erdfelt <[email protected]> Fixes: 444d13f ("modules: add ro_after_init support") Acked-by: Jessica Yu <[email protected]> Reviewed-by: Petr Mladek <[email protected]> Reviewed-by: Miroslav Benes <[email protected]> Signed-off-by: Josh Poimboeuf <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>

The mapper may be NULL when called from register_ftrace_function_probe() with probe->data == NULL. This issue can be reproduced as follow (it may be covered by compiler optimization sometime): / # cat /sys/kernel/debug/tracing/set_ftrace_filter #### all functions enabled #### / # echo foo_bar:dump > /sys/kernel/debug/tracing/set_ftrace_filter [ 206.949100] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 206.952402] Mem abort info: [ 206.952819] ESR = 0x96000006 [ 206.955326] Exception class = DABT (current EL), IL = 32 bits [ 206.955844] SET = 0, FnV = 0 [ 206.956272] EA = 0, S1PTW = 0 [ 206.956652] Data abort info: [ 206.957320] ISV = 0, ISS = 0x00000006 [ 206.959271] CM = 0, WnR = 0 [ 206.959938] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000419f3a000 [ 206.960483] [0000000000000000] pgd=0000000411a87003, pud=0000000411a83003, pmd=0000000000000000 [ 206.964953] Internal error: Oops: 96000006 [#1] SMP [ 206.971122] Dumping ftrace buffer: [ 206.973677] (ftrace buffer empty) [ 206.975258] Modules linked in: [ 206.976631] Process sh (pid: 281, stack limit = 0x(____ptrval____)) [ 206.978449] CPU: 10 PID: 281 Comm: sh Not tainted 5.2.0-rc1+ linux-kernel-labs#17 [ 206.978955] Hardware name: linux,dummy-virt (DT) [ 206.979883] pstate: 60000005 (nZCv daif -PAN -UAO) [ 206.980499] pc : free_ftrace_func_mapper+0x2c/0x118 [ 206.980874] lr : ftrace_count_free+0x68/0x80 [ 206.982539] sp : ffff0000182f3ab0 [ 206.983102] x29: ffff0000182f3ab0 x28: ffff8003d0ec1700 [ 206.983632] x27: ffff000013054b40 x26: 0000000000000001 [ 206.984000] x25: ffff00001385f000 x24: 0000000000000000 [ 206.984394] x23: ffff000013453000 x22: ffff000013054000 [ 206.984775] x21: 0000000000000000 x20: ffff00001385fe28 [ 206.986575] x19: ffff000013872c30 x18: 0000000000000000 [ 206.987111] x17: 0000000000000000 x16: 0000000000000000 [ 206.987491] x15: ffffffffffffffb0 x14: 0000000000000000 [ 206.987850] x13: 000000000017430e x12: 0000000000000580 [ 206.988251] x11: 0000000000000000 x10: cccccccccccccccc [ 206.988740] x9 : 0000000000000000 x8 : ffff000013917550 [ 206.990198] x7 : ffff000012fac2e8 x6 : ffff000012fac000 [ 206.991008] x5 : ffff0000103da588 x4 : 0000000000000001 [ 206.991395] x3 : 0000000000000001 x2 : ffff000013872a28 [ 206.991771] x1 : 0000000000000000 x0 : 0000000000000000 [ 206.992557] Call trace: [ 206.993101] free_ftrace_func_mapper+0x2c/0x118 [ 206.994827] ftrace_count_free+0x68/0x80 [ 206.995238] release_probe+0xfc/0x1d0 [ 206.995555] register_ftrace_function_probe+0x4a8/0x868 [ 206.995923] ftrace_trace_probe_callback.isra.4+0xb8/0x180 [ 206.996330] ftrace_dump_callback+0x50/0x70 [ 206.996663] ftrace_regex_write.isra.29+0x290/0x3a8 [ 206.997157] ftrace_filter_write+0x44/0x60 [ 206.998971] __vfs_write+0x64/0xf0 [ 206.999285] vfs_write+0x14c/0x2f0 [ 206.999591] ksys_write+0xbc/0x1b0 [ 206.999888] __arm64_sys_write+0x3c/0x58 [ 207.000246] el0_svc_common.constprop.0+0x408/0x5f0 [ 207.000607] el0_svc_handler+0x144/0x1c8 [ 207.000916] el0_svc+0x8/0xc [ 207.003699] Code: aa0003f8 a9025bf5 aa0103f5 f946ea80 (f9400303) [ 207.008388] ---[ end trace 7b6d11b5f542bdf1 ]--- [ 207.010126] Kernel panic - not syncing: Fatal exception [ 207.011322] SMP: stopping secondary CPUs [ 207.013956] Dumping ftrace buffer: [ 207.014595] (ftrace buffer empty) [ 207.015632] Kernel Offset: disabled [ 207.017187] CPU features: 0x002,20006008 [ 207.017985] Memory Limit: none [ 207.019825] ---[ end Kernel panic - not syncing: Fatal exception ]--- Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Wei Li <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>

Reinhard Speyerer says: ==================== qmi_wwan: fix QMAP handling This series addresses the following issues observed when using the QMAP support of the qmi_wwan driver: 1. The QMAP code in the qmi_wwan driver is based on the CodeAurora GobiNet driver ([1], [2]) which does not process QMAP padding in the RX path correctly. This causes qmimux_rx_fixup() to pass incorrect data to the IP stack when padding is used. 2. qmimux devices currently lack proper network device usage statistics. 3. RCU stalls on device disconnect with QMAP activated like this # echo Y > /sys/class/net/wwan0/qmi/raw_ip # echo 1 > /sys/class/net/wwan0/qmi/add_mux # echo 2 > /sys/class/net/wwan0/qmi/add_mux # echo 3 > /sys/class/net/wwan0/qmi/add_mux have been observed in certain setups: [ 2273.676593] option1 ttyUSB16: GSM modem (1-port) converter now disconnected from ttyUSB16 [ 2273.676617] option 6-1.2:1.0: device disconnected [ 2273.676774] WARNING: CPU: 1 PID: 141 at kernel/rcu/tree_plugin.h:342 rcu_note_context_switch+0x2a/0x3d0 [ 2273.676776] Modules linked in: option qmi_wwan cdc_mbim cdc_ncm qcserial cdc_wdm usb_wwan sierra sierra_net usbnet mii edd coretemp iptable_mangle ip6_tables iptable_filter ip_tables cdc_acm dm_mod dax iTCO_wdt evdev iTCO_vendor_support sg ftdi_sio usbserial e1000e ptp pps_core i2c_i801 ehci_pci button lpc_ich i2c_core mfd_core uhci_hcd ehci_hcd rtc_cmos usbcore usb_common sd_mod fan ata_piix thermal [ 2273.676817] CPU: 1 PID: 141 Comm: kworker/1:1 Not tainted 4.19.38-rsp-1 #1 [ 2273.676819] Hardware name: Not Applicable Not Applicable /CX-GS/GM45-GL40 , BIOS V1.11 03/23/2011 [ 2273.676828] Workqueue: usb_hub_wq hub_event [usbcore] [ 2273.676832] EIP: rcu_note_context_switch+0x2a/0x3d0 [ 2273.676834] Code: 55 89 e5 57 56 89 c6 53 83 ec 14 89 45 f0 e8 5d ff ff ff 89 f0 64 8b 3d 24 a6 86 c0 84 c0 8b 87 04 02 00 00 75 7a 85 c0 7e 7a <0f> 0b 80 bf 08 02 00 00 00 0f 84 87 00 00 00 e8 b2 e2 ff ff bb dc [ 2273.676836] EAX: 00000001 EBX: f614bc00 ECX: 00000001 EDX: c0715b81 [ 2273.676838] ESI: 00000000 EDI: f18beb40 EBP: f1a3dc20 ESP: f1a3dc00 [ 2273.676840] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010002 [ 2273.676842] CR0: 80050033 CR2: b7e97230 CR3: 2f9c4000 CR4: 000406b0 [ 2273.676843] Call Trace: [ 2273.676847] ? preempt_count_add+0xa5/0xc0 [ 2273.676852] __schedule+0x4e/0x4f0 [ 2273.676855] ? __queue_work+0xf1/0x2a0 [ 2273.676858] ? _raw_spin_lock_irqsave+0x14/0x40 [ 2273.676860] ? preempt_count_add+0x52/0xc0 [ 2273.676862] schedule+0x33/0x80 [ 2273.676865] _synchronize_rcu_expedited+0x24e/0x280 [ 2273.676867] ? rcu_accelerate_cbs_unlocked+0x70/0x70 [ 2273.676871] ? wait_woken+0x70/0x70 [ 2273.676873] ? rcu_accelerate_cbs_unlocked+0x70/0x70 [ 2273.676875] ? _synchronize_rcu_expedited+0x280/0x280 [ 2273.676877] synchronize_rcu_expedited+0x22/0x30 [ 2273.676881] synchronize_net+0x25/0x30 [ 2273.676885] dev_deactivate_many+0x133/0x230 [ 2273.676887] ? preempt_count_add+0xa5/0xc0 [ 2273.676890] __dev_close_many+0x4d/0xc0 [ 2273.676892] ? skb_dequeue+0x40/0x50 [ 2273.676895] dev_close_many+0x5d/0xd0 [ 2273.676898] rollback_registered_many+0xbf/0x4c0 [ 2273.676901] ? raw_notifier_call_chain+0x1a/0x20 [ 2273.676904] ? call_netdevice_notifiers_info+0x23/0x60 [ 2273.676906] ? netdev_master_upper_dev_get+0xe/0x70 [ 2273.676908] rollback_registered+0x1f/0x30 [ 2273.676911] unregister_netdevice_queue+0x47/0xb0 [ 2273.676915] qmimux_unregister_device+0x1f/0x30 [qmi_wwan] [ 2273.676917] qmi_wwan_disconnect+0x5d/0x90 [qmi_wwan] ... [ 2273.677001] ---[ end trace 0fcc5f88496b485a ]--- [ 2294.679136] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: [ 2294.679140] rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P141 [ 2294.679144] rcu: (detected by 0, t=21002 jiffies, g=265857, q=8446) [ 2294.679148] kworker/1:1 D 0 141 2 0x80000000 In addition the permitted QMAP mux_id value range is extended for compatibility with ip(8) and the rmnet driver. Reinhard [1]: https://portland.source.codeaurora.org/patches/quic/gobi [2]: https://portland.source.codeaurora.org/quic/qsdk/oss/lklm/gobinet/ ==================== Tested-by: Daniele Palmas <[email protected]> Acked-by: Bjørn Mork <[email protected]> Signed-off-by: David S. Miller <[email protected]>

We should use irq disabled mode when read/write hda registers from thread context, as we need to hold the same bus->reg_lock in interrupt context hda_dsp_stream_interrupt(), otherwise, when we are holding the lock in hda_dsp_stream_hw_free() and the interrupt arrives, we will get deadlock in the interrupt handler. Error logs like this: [ 5.603606] CPU0 [ 5.603606] ---- [ 5.603607] lock(&(&bus->reg_lock)->rlock); [ 5.603608] <Interrupt> [ 5.603609] lock(&(&bus->reg_lock)->rlock); [ 5.603610] *** DEADLOCK *** [ 5.603611] 2 locks held by pulseaudio/2329: [ 5.603612] #0: 000000005fcf26c6 (&card->mutex/1){+.+.}, at: dpcm_fe_dai_hw_free+0x2b/0x110 [snd_soc_core] [ 5.603619] #1: 00000000ef369faf (&rtd->pcm_mutex){+.+.}, at: soc_pcm_hw_free+0x2e/0x1c0 [snd_soc_core] The fix is simple, let's switch to use spin_lock/unlock_irq(). Reported-by: Xun Zhang <[email protected]> Signed-off-by: Keyon Jie <[email protected]> Signed-off-by: Pierre-Louis Bossart <[email protected]> Signed-off-by: Mark Brown <[email protected]>

Commit c1fe190 ("powerpc: Add force enable of DAWR on P9 option") screwed up some assembler and corrupted a pointer in r3. This resulted in crashes like the below: BUG: Kernel NULL pointer dereference at 0x000013bf Faulting instruction address: 0xc00000000010b044 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix MMU=Hash SMP NR_CPUS=2048 NUMA pSeries CPU: 8 PID: 1771 Comm: qemu-system-ppc Kdump: loaded Not tainted 5.2.0-rc4+ #3 NIP: c00000000010b044 LR: c0080000089dacf4 CTR: c00000000010aff4 REGS: c00000179b397710 TRAP: 0300 Not tainted (5.2.0-rc4+) MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 42244842 XER: 00000000 CFAR: c00000000010aff8 DAR: 00000000000013bf DSISR: 42000000 IRQMASK: 0 GPR00: c0080000089dd6bc c00000179b3979a0 c008000008a04300 ffffffffffffffff GPR04: 0000000000000000 0000000000000003 000000002444b05d c0000017f11c45d0 ... NIP kvmppc_h_set_dabr+0x50/0x68 LR kvmppc_pseries_do_hcall+0xa3c/0xeb0 [kvm_hv] Call Trace: 0xc0000017f11c0000 (unreliable) kvmppc_vcpu_run_hv+0x694/0xec0 [kvm_hv] kvmppc_vcpu_run+0x34/0x48 [kvm] kvm_arch_vcpu_ioctl_run+0x2f4/0x400 [kvm] kvm_vcpu_ioctl+0x460/0x850 [kvm] do_vfs_ioctl+0xe4/0xb40 ksys_ioctl+0xc4/0x110 sys_ioctl+0x28/0x80 system_call+0x5c/0x70 Instruction dump: 4082fff4 4c00012c 38600000 4e800020 e96280c0 896b0000 2c2b0000 3860ffff 4d820020 50852e74 508516f6 78840724 <f88313c0> f8a313c8 7c942ba6 7cbc2ba6 Fix the bug by only changing r3 when we are returning immediately. Fixes: c1fe190 ("powerpc: Add force enable of DAWR on P9 option") Signed-off-by: Michael Neuling <[email protected]> Signed-off-by: Suraj Jitindar Singh <[email protected]> Reported-by: Cédric Le Goater <[email protected]> Signed-off-by: Michael Ellerman <[email protected]>

The kernel panic was observed during iSCSI discovery via offload with below call trace, [ 2115.646901] BUG: unable to handle kernel NULL pointer dereference at (null) [ 2115.646909] IP: [<ffffffffacf7f0cc>] strncmp+0xc/0x60 [ 2115.646927] PGD 0 [ 2115.646932] Oops: 0000 [#1] SMP [ 2115.647107] CPU: 24 PID: 264 Comm: kworker/24:1 Kdump: loaded Tainted: G OE ------------ 3.10.0-957.el7.x86_64 #1 [ 2115.647133] Workqueue: slowpath-13:00. qed_slowpath_task [qed] [ 2115.647135] task: ffff8d66af80b0c0 ti: ffff8d66afb80000 task.ti: ffff8d66afb80000 [ 2115.647136] RIP: 0010:[<ffffffffacf7f0cc>] [<ffffffffacf7f0cc>] strncmp+0xc/0x60 [ 2115.647141] RSP: 0018:ffff8d66afb83c68 EFLAGS: 00010206 [ 2115.647143] RAX: 0000000000000001 RBX: 0000000000000007 RCX: 000000000000000a [ 2115.647144] RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff8d632b3ba040 [ 2115.647145] RBP: ffff8d66afb83c68 R08: 0000000000000000 R09: 000000000000ffff [ 2115.647147] R10: 0000000000000007 R11: 0000000000000800 R12: ffff8d66a30007a0 [ 2115.647148] R13: ffff8d66747a3c10 R14: ffff8d632b3ba000 R15: ffff8d66747a32f8 [ 2115.647149] FS: 0000000000000000(0000) GS:ffff8d66aff00000(0000) knlGS:0000000000000000 [ 2115.647151] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2115.647152] CR2: 0000000000000000 CR3: 0000000509610000 CR4: 00000000007607e0 [ 2115.647153] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2115.647154] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 2115.647155] PKRU: 00000000 [ 2115.647157] Call Trace: [ 2115.647165] [<ffffffffc0634cc5>] qedi_get_protocol_tlv_data+0x2c5/0x510 [qedi] [ 2115.647184] [<ffffffffc05968f5>] ? qed_mfw_process_tlv_req+0x245/0xbe0 [qed] [ 2115.647195] [<ffffffffc05496cb>] qed_mfw_fill_tlv_data+0x4b/0xb0 [qed] [ 2115.647206] [<ffffffffc0596911>] qed_mfw_process_tlv_req+0x261/0xbe0 [qed] [ 2115.647215] [<ffffffffacce0e8e>] ? dequeue_task_fair+0x41e/0x660 [ 2115.647221] [<ffffffffacc2a59e>] ? __switch_to+0xce/0x580 [ 2115.647230] [<ffffffffc0546013>] qed_slowpath_task+0xa3/0x160 [qed] [ 2115.647278] RIP [<ffffffffacf7f0cc>] strncmp+0xc/0x60 Fix kernel panic by validating the session targetname before providing TLV data and confirming the presence of boot targets. Signed-off-by: Nilesh Javali <[email protected]> Reviewed-by: Lee Duncan <[email protected]> Reviewed-by: Chris Leech <[email protected]> Signed-off-by: Martin K. Petersen <[email protected]>

After commit d4fc506 ("mm: switch s_mem and slab_cache in struct page") page->mapping will be re-used by slab allocations and page->mapping->host will be used in balance_dirty_pages_ratelimited() as an inode member but it's not an inode in fact and leads an oops. [ 159.906493] Unable to handle kernel paging request at virtual address ffff200012d90be8 [ 159.908029] Mem abort info: [ 159.908552] ESR = 0x96000007 [ 159.909138] Exception class = DABT (current EL), IL = 32 bits [ 159.910155] SET = 0, FnV = 0 [ 159.910690] EA = 0, S1PTW = 0 [ 159.911241] Data abort info: [ 159.911846] ISV = 0, ISS = 0x00000007 [ 159.912567] CM = 0, WnR = 0 [ 159.913105] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000042acd000 [ 159.914269] [ffff200012d90be8] pgd=000000043ffff003, pud=000000043fffe003, pmd=000000043fffa003, pte=0000000000000000 [ 159.916280] Internal error: Oops: 96000007 [#1] SMP [ 159.917195] Dumping ftrace buffer: [ 159.917845] (ftrace buffer empty) [ 159.918521] Modules linked in: uio_dev(OE) [ 159.919276] CPU: 1 PID: 295 Comm: uio_test Tainted: G OE 5.2.0-rc4+ linux-kernel-labs#46 [ 159.920859] Hardware name: linux,dummy-virt (DT) [ 159.921815] pstate: 60000005 (nZCv daif -PAN -UAO) [ 159.922809] pc : balance_dirty_pages_ratelimited+0x68/0xc38 [ 159.923965] lr : fault_dirty_shared_page.isra.8+0xe4/0x100 [ 159.925134] sp : ffff800368a77ae0 [ 159.925824] x29: ffff800368a77ae0 x28: 1ffff0006d14ce1a [ 159.926906] x27: ffff800368a670d0 x26: ffff800368a67120 [ 159.927985] x25: 1ffff0006d10f5fe x24: ffff200012d90be8 [ 159.929089] x23: ffff200013732000 x22: ffff80036ec03200 [ 159.930172] x21: ffff200012d90bc0 x20: 1fffe400025b217d [ 159.931253] x19: ffff80036ec03200 x18: 0000000000000000 [ 159.932348] x17: 0000000000000000 x16: 0ffffe0000010208 [ 159.933439] x15: 0000000000000000 x14: 0000000000000000 [ 159.934518] x13: 0000000000000000 x12: 0000000000000000 [ 159.935596] x11: 1fffefc001b452c0 x10: ffff0fc001b452c0 [ 159.936697] x9 : dfff200000000000 x8 : dfff200000000001 [ 159.937781] x7 : ffff7e000da29607 x6 : ffff0fc001b452c1 [ 159.938859] x5 : ffff0fc001b452c1 x4 : ffff0fc001b452c1 [ 159.939944] x3 : ffff200010523ad4 x2 : 1fffe400026e659b [ 159.941065] x1 : dfff200000000000 x0 : ffff200013732cd8 [ 159.942205] Call trace: [ 159.942732] balance_dirty_pages_ratelimited+0x68/0xc38 [ 159.943797] fault_dirty_shared_page.isra.8+0xe4/0x100 [ 159.944867] do_fault+0x608/0x1250 [ 159.945571] __handle_mm_fault+0x93c/0xfb8 [ 159.946412] handle_mm_fault+0x1c0/0x360 [ 159.947224] do_page_fault+0x358/0x8d0 [ 159.947993] do_translation_fault+0xf8/0x124 [ 159.948884] do_mem_abort+0x70/0x190 [ 159.949624] el0_da+0x24/0x28 According another commit 5e901d0 ("scsi: qedi: Fix bad pte call trace when iscsiuio is stopped."), using kmalloc also cause other problem. But the documentation about UIO_MEM_LOGICAL allows using kmalloc(), remove and don't allow using kmalloc() in documentation. Signed-off-by: Yang Yingliang <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

…_domain_lock" This reverts commit 7560cc3. With 5.2.0-rc5 I can easily trigger this with lockdep and iommu=pt: ====================================================== WARNING: possible circular locking dependency detected 5.2.0-rc5 linux-kernel-labs#78 Not tainted ------------------------------------------------------ swapper/0/1 is trying to acquire lock: 00000000ea2b3beb (&(&iommu->lock)->rlock){+.+.}, at: domain_context_mapping_one+0xa5/0x4e0 but task is already holding lock: 00000000a681907b (device_domain_lock){....}, at: domain_context_mapping_one+0x8d/0x4e0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (device_domain_lock){....}: _raw_spin_lock_irqsave+0x3c/0x50 dmar_insert_one_dev_info+0xbb/0x510 domain_add_dev_info+0x50/0x90 dev_prepare_static_identity_mapping+0x30/0x68 intel_iommu_init+0xddd/0x1422 pci_iommu_init+0x16/0x3f do_one_initcall+0x5d/0x2b4 kernel_init_freeable+0x218/0x2c1 kernel_init+0xa/0x100 ret_from_fork+0x3a/0x50 -> #0 (&(&iommu->lock)->rlock){+.+.}: lock_acquire+0x9e/0x170 _raw_spin_lock+0x25/0x30 domain_context_mapping_one+0xa5/0x4e0 pci_for_each_dma_alias+0x30/0x140 dmar_insert_one_dev_info+0x3b2/0x510 domain_add_dev_info+0x50/0x90 dev_prepare_static_identity_mapping+0x30/0x68 intel_iommu_init+0xddd/0x1422 pci_iommu_init+0x16/0x3f do_one_initcall+0x5d/0x2b4 kernel_init_freeable+0x218/0x2c1 kernel_init+0xa/0x100 ret_from_fork+0x3a/0x50 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(device_domain_lock); lock(&(&iommu->lock)->rlock); lock(device_domain_lock); lock(&(&iommu->lock)->rlock); *** DEADLOCK *** 2 locks held by swapper/0/1: #0: 00000000033eb13d (dmar_global_lock){++++}, at: intel_iommu_init+0x1e0/0x1422 #1: 00000000a681907b (device_domain_lock){....}, at: domain_context_mapping_one+0x8d/0x4e0 stack backtrace: CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc5 linux-kernel-labs#78 Hardware name: LENOVO 20KGS35G01/20KGS35G01, BIOS N23ET50W (1.25 ) 06/25/2018 Call Trace: dump_stack+0x85/0xc0 print_circular_bug.cold.57+0x15c/0x195 __lock_acquire+0x152a/0x1710 lock_acquire+0x9e/0x170 ? domain_context_mapping_one+0xa5/0x4e0 _raw_spin_lock+0x25/0x30 ? domain_context_mapping_one+0xa5/0x4e0 domain_context_mapping_one+0xa5/0x4e0 ? domain_context_mapping_one+0x4e0/0x4e0 pci_for_each_dma_alias+0x30/0x140 dmar_insert_one_dev_info+0x3b2/0x510 domain_add_dev_info+0x50/0x90 dev_prepare_static_identity_mapping+0x30/0x68 intel_iommu_init+0xddd/0x1422 ? printk+0x58/0x6f ? lockdep_hardirqs_on+0xf0/0x180 ? do_early_param+0x8e/0x8e ? e820__memblock_setup+0x63/0x63 pci_iommu_init+0x16/0x3f do_one_initcall+0x5d/0x2b4 ? do_early_param+0x8e/0x8e ? rcu_read_lock_sched_held+0x55/0x60 ? do_early_param+0x8e/0x8e kernel_init_freeable+0x218/0x2c1 ? rest_init+0x230/0x230 kernel_init+0xa/0x100 ret_from_fork+0x3a/0x50 domain_context_mapping_one() is taking device_domain_lock first then iommu lock, while dmar_insert_one_dev_info() is doing the reverse. That should be introduced by commit: 7560cc3 ("iommu/vt-d: Fix lock inversion between iommu->lock and device_domain_lock", 2019-05-27) So far I still cannot figure out how the previous deadlock was triggered (I cannot find iommu lock taken before calling of iommu_flush_dev_iotlb()), however I'm pretty sure that that change should be incomplete at least because it does not fix all the places so we're still taking the locks in different orders, while reverting that commit is very clean to me so far that we should always take device_domain_lock first then the iommu lock. We can continue to try to find the real culprit mentioned in 7560cc3, but for now I think we should revert it to fix current breakage. CC: Joerg Roedel <[email protected]> CC: Lu Baolu <[email protected]> CC: [email protected] Signed-off-by: Peter Xu <[email protected]> Tested-by: Chris Wilson <[email protected]> Signed-off-by: Joerg Roedel <[email protected]>

Stephen reports: I hit the following General Protection Fault when testing io_uring via the io_uring engine in fio. This was on a VM running 5.2-rc5 and the latest version of fio. The issue occurs for both null_blk and fake NVMe drives. I have not tested bare metal or real NVMe SSDs. The fio script used is given below. [io_uring] time_based=1 runtime=60 filename=/dev/nvme2n1 (note /dev/nullb0 also fails) ioengine=io_uring bs=4k rw=readwrite direct=1 fixedbufs=1 sqthread_poll=1 sqthread_poll_cpu=0 general protection fault: 0000 [#1] SMP PTI CPU: 0 PID: 872 Comm: io_uring-sq Not tainted 5.2.0-rc5-cpacket-io-uring #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 RIP: 0010:fput_many+0x7/0x90 Code: 01 48 85 ff 74 17 55 48 89 e5 53 48 8b 1f e8 a0 f9 ff ff 48 85 db 48 89 df 75 f0 5b 5d f3 c3 0f 1f 40 00 0f 1f 44 00 00 89 f6 <f0> 48 29 77 38 74 01 c3 55 48 89 e5 53 48 89 fb 65 48 \ RSP: 0018:ffffadeb817ebc50 EFLAGS: 00010246 RAX: 0000000000000004 RBX: ffff8f46ad477480 RCX: 0000000000001805 RDX: 0000000000000000 RSI: 0000000000000001 RDI: f18b51b9a39552b5 RBP: ffffadeb817ebc58 R08: ffff8f46b7a318c0 R09: 000000000000015d R10: ffffadeb817ebce8 R11: 0000000000000020 R12: ffff8f46ad4cd000 R13: 00000000fffffff7 R14: ffffadeb817ebe30 R15: 0000000000000004 FS: 0000000000000000(0000) GS:ffff8f46b7a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055828f0bbbf0 CR3: 0000000232176004 CR4: 00000000003606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? fput+0x13/0x20 io_free_req+0x20/0x40 io_put_req+0x1b/0x20 io_submit_sqe+0x40a/0x680 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 io_submit_sqes+0xb9/0x160 ? io_submit_sqes+0xb9/0x160 ? __switch_to_asm+0x40/0x70 ? __switch_to_asm+0x34/0x70 ? __schedule+0x3f2/0x6a0 ? __switch_to_asm+0x34/0x70 io_sq_thread+0x1af/0x470 ? __switch_to_asm+0x34/0x70 ? wait_woken+0x80/0x80 ? __switch_to+0x85/0x410 ? __switch_to_asm+0x40/0x70 ? __switch_to_asm+0x34/0x70 ? __schedule+0x3f2/0x6a0 kthread+0x105/0x140 ? io_submit_sqes+0x160/0x160 ? kthread+0x105/0x140 ? io_submit_sqes+0x160/0x160 ? kthread_destroy_worker+0x50/0x50 ret_from_fork+0x35/0x40 which occurs because using a kernel side submission thread isn't valid without using fixed files (registered through io_uring_register()). This causes io_uring to put the request after logging an error, but before the file field is set in the request. If it happens to be non-zero, we attempt to fput() garbage. Fix this by ensuring that req->file is initialized when the request is allocated. Cc: [email protected] # 5.1+ Reported-by: Stephen Bates <[email protected]> Tested-by: Stephen Bates <[email protected]> Signed-off-by: Jens Axboe <[email protected]>

Kyle has reported occasional crashes when booting a kernel in 5-level paging mode with KASLR enabled: WARNING: CPU: 0 PID: 0 at arch/x86/mm/init_64.c:87 phys_p4d_init+0x1d4/0x1ea RIP: 0010:phys_p4d_init+0x1d4/0x1ea Call Trace: __kernel_physical_mapping_init+0x10a/0x35c kernel_physical_mapping_init+0xe/0x10 init_memory_mapping+0x1aa/0x3b0 init_range_memory_mapping+0xc8/0x116 init_mem_mapping+0x225/0x2eb setup_arch+0x6ff/0xcf5 start_kernel+0x64/0x53b ? copy_bootdata+0x1f/0xce x86_64_start_reservations+0x24/0x26 x86_64_start_kernel+0x8a/0x8d secondary_startup_64+0xb6/0xc0 which causes later: BUG: unable to handle page fault for address: ff484d019580eff8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page BAD Oops: 0000 [#1] SMP NOPTI RIP: 0010:fill_pud+0x13/0x130 Call Trace: set_pte_vaddr_p4d+0x2e/0x50 set_pte_vaddr+0x6f/0xb0 __native_set_fixmap+0x28/0x40 native_set_fixmap+0x39/0x70 register_lapic_address+0x49/0xb6 early_acpi_boot_init+0xa5/0xde setup_arch+0x944/0xcf5 start_kernel+0x64/0x53b Kyle bisected the issue to commit b569c18 ("x86/mm/KASLR: Reduce randomization granularity for 5-level paging to 1GB") Before this commit PAGE_OFFSET was always aligned to P4D_SIZE when booting 5-level paging mode. But now only PUD_SIZE alignment is guaranteed. In the case I was able to reproduce the following vaddr/paddr values were observed in phys_p4d_init(): Iteration vaddr paddr 1 0xff4228027fe00000 0x033fe00000 2 0xff42287f40000000 0x8000000000 'vaddr' in both cases belongs to the same p4d entry. But due to the original assumption that PAGE_OFFSET is aligned to P4D_SIZE this overlap cannot be handled correctly. The code assumes strictly aligned entries and unconditionally increments the index into the P4D table, which creates false duplicate entries. Once the index reaches the end, the last entry in the page table is missing. Aside of that the 'paddr >= paddr_end' condition can evaluate wrong which causes an P4D entry to be cleared incorrectly. Change the loop in phys_p4d_init() to walk purely based on virtual addresses like __kernel_physical_mapping_init() does. This makes it work correctly with unaligned virtual addresses. Fixes: b569c18 ("x86/mm/KASLR: Reduce randomization granularity for 5-level paging to 1GB") Reported-by: Kyle Pelton <[email protected]> Signed-off-by: Kirill A. Shutemov <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Tested-by: Kyle Pelton <[email protected]> Acked-by: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]

Donald reported this sequence: ip next add id 1 blackhole ip next add id 2 blackhole ip ro add 1.1.1.1/32 nhid 1 ip ro add 1.1.1.2/32 nhid 2 would cause a crash. Backtrace is: [ 151.302790] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI [ 151.304043] CPU: 1 PID: 277 Comm: ip Not tainted 5.3.0-rc5+ linux-kernel-labs#37 [ 151.305078] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1 04/01/2014 [ 151.306526] RIP: 0010:fib_add_nexthop+0x8b/0x2aa [ 151.307343] Code: 35 f7 81 48 8d 14 01 c7 02 f1 f1 f1 f1 c7 42 04 01 f4 f4 f4 48 89 f2 48 c1 ea 03 65 48 8b 0c 25 28 00 00 00 48 89 4d d0 31 c9 <80> 3c 02 00 74 08 48 89 f7 e8 1a e8 53 ff be 08 00 00 00 4c 89 e7 [ 151.310549] RSP: 0018:ffff888116c27340 EFLAGS: 00010246 [ 151.311469] RAX: dffffc0000000000 RBX: ffff8881154ece00 RCX: 0000000000000000 [ 151.312713] RDX: 0000000000000004 RSI: 0000000000000020 RDI: ffff888115649b40 [ 151.313968] RBP: ffff888116c273d8 R08: ffffed10221e3757 R09: ffff888110f1bab8 [ 151.315212] R10: 0000000000000001 R11: ffff888110f1bab3 R12: ffff888115649b40 [ 151.316456] R13: 0000000000000020 R14: ffff888116c273b0 R15: ffff888115649b40 [ 151.317707] FS: 00007f60b4d8d800(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000 [ 151.319113] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 151.320119] CR2: 0000555671ffdc00 CR3: 00000001136ba005 CR4: 0000000000020ee0 [ 151.321367] Call Trace: [ 151.321820] ? fib_nexthop_info+0x635/0x635 [ 151.322572] fib_dump_info+0xaa4/0xde0 [ 151.323247] ? fib_create_info+0x2431/0x2431 [ 151.324008] ? napi_alloc_frag+0x2a/0x2a [ 151.324711] rtmsg_fib+0x2c4/0x3be [ 151.325339] fib_table_insert+0xe2f/0xeee ... fib_dump_info incorrectly has nhs = 0 for blackhole nexthops, so it believes the nexthop object is a multipath group (nhs != 1) and ends up down the nexthop_mpath_fill_node() path which is wrong for a blackhole. The blackhole check in nexthop_num_path is leftover from early days of the blackhole implementation which did not initialize the device. In the end the design was simpler (fewer special case checks) to set the device to loopback in nh_info, so the check in nexthop_num_path should have been removed. Fixes: 430a049 ("nexthop: Add support for nexthop groups") Reported-by: Donald Sharp <[email protected]> Signed-off-by: David Ahern <[email protected]> Signed-off-by: David S. Miller <[email protected]>

After commit baeabab ("tun: return NET_XMIT_DROP for dropped packets"), when tun_net_xmit drop packets, it will free skb and return NET_XMIT_DROP, netpoll_send_skb_on_dev will run into following use after free cases: 1. retry netpoll_start_xmit with freed skb; 2. queue freed skb in npinfo->txq. queue_process will also run into use after free case. hit netpoll_send_skb_on_dev first case with following kernel log: [ 117.864773] kernel BUG at mm/slub.c:306! [ 117.864773] invalid opcode: 0000 [#1] SMP PTI [ 117.864774] CPU: 3 PID: 2627 Comm: loop_printmsg Kdump: loaded Tainted: P OE 5.3.0-050300rc5-generic #201908182231 [ 117.864775] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 117.864775] RIP: 0010:kmem_cache_free+0x28d/0x2b0 [ 117.864781] Call Trace: [ 117.864781] ? tun_net_xmit+0x21c/0x460 [ 117.864781] kfree_skbmem+0x4e/0x60 [ 117.864782] kfree_skb+0x3a/0xa0 [ 117.864782] tun_net_xmit+0x21c/0x460 [ 117.864782] netpoll_start_xmit+0x11d/0x1b0 [ 117.864788] netpoll_send_skb_on_dev+0x1b8/0x200 [ 117.864789] __br_forward+0x1b9/0x1e0 [bridge] [ 117.864789] ? skb_clone+0x53/0xd0 [ 117.864790] ? __skb_clone+0x2e/0x120 [ 117.864790] deliver_clone+0x37/0x50 [bridge] [ 117.864790] maybe_deliver+0x89/0xc0 [bridge] [ 117.864791] br_flood+0x6c/0x130 [bridge] [ 117.864791] br_dev_xmit+0x315/0x3c0 [bridge] [ 117.864792] netpoll_start_xmit+0x11d/0x1b0 [ 117.864792] netpoll_send_skb_on_dev+0x1b8/0x200 [ 117.864792] netpoll_send_udp+0x2c6/0x3e8 [ 117.864793] write_msg+0xd9/0xf0 [netconsole] [ 117.864793] console_unlock+0x386/0x4e0 [ 117.864793] vprintk_emit+0x17e/0x280 [ 117.864794] vprintk_default+0x29/0x50 [ 117.864794] vprintk_func+0x4c/0xbc [ 117.864794] printk+0x58/0x6f [ 117.864795] loop_fun+0x24/0x41 [printmsg_loop] [ 117.864795] kthread+0x104/0x140 [ 117.864795] ? 0xffffffffc05b1000 [ 117.864796] ? kthread_park+0x80/0x80 [ 117.864796] ret_from_fork+0x35/0x40 Signed-off-by: Feng Sun <[email protected]> Signed-off-by: Xiaojun Zhao <[email protected]> Signed-off-by: David S. Miller <[email protected]>

The compaction code already marks pages as offline when it enqueues pages in the ballooned page list, and removes the mapping when the pages are removed from the list. VMware balloon also updates the flags, instead of letting the balloon-compaction logic handle it, which causes the assertion VM_BUG_ON_PAGE(!PageOffline(page)) to fire, when __ClearPageOffline is called the second time. This causes the following crash. [ 487.104520] kernel BUG at include/linux/page-flags.h:749! [ 487.106364] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI [ 487.107681] CPU: 7 PID: 1106 Comm: kworker/7:3 Not tainted 5.3.0-rc5balloon linux-kernel-labs#227 [ 487.109196] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 12/12/2018 [ 487.111452] Workqueue: events_freezable vmballoon_work [vmw_balloon] [ 487.112779] RIP: 0010:vmballoon_release_page_list+0xaa/0x100 [vmw_balloon] [ 487.114200] Code: fe 48 c1 e7 06 4c 01 c7 8b 47 30 41 89 c1 41 81 e1 00 01 00 f0 41 81 f9 00 00 00 f0 74 d3 48 c7 c6 08 a1 a1 c0 e8 06 0d e7 ea <0f> 0b 44 89 f6 4c 89 c7 e8 49 9c e9 ea 49 8d 75 08 49 8b 45 08 4d [ 487.118033] RSP: 0018:ffffb82f012bbc98 EFLAGS: 00010246 [ 487.119135] RAX: 0000000000000037 RBX: 0000000000000001 RCX: 0000000000000006 [ 487.120601] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9a85b6bd7620 [ 487.122071] RBP: ffffb82f012bbcc0 R08: 0000000000000001 R09: 0000000000000000 [ 487.123536] R10: 0000000000000000 R11: 0000000000000000 R12: ffffb82f012bbd00 [ 487.125002] R13: ffffe97f4598d9c0 R14: 0000000000000000 R15: ffffb82f012bbd34 [ 487.126463] FS: 0000000000000000(0000) GS:ffff9a85b6bc0000(0000) knlGS:0000000000000000 [ 487.128110] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 487.129316] CR2: 00007ffe6e413ea0 CR3: 0000000230b18001 CR4: 00000000003606e0 [ 487.130812] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 487.132283] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 487.133749] Call Trace: [ 487.134333] vmballoon_deflate+0x22c/0x390 [vmw_balloon] [ 487.135468] vmballoon_work+0x6e7/0x913 [vmw_balloon] [ 487.136711] ? process_one_work+0x21a/0x5e0 [ 487.138581] process_one_work+0x298/0x5e0 [ 487.139926] ? vmballoon_migratepage+0x310/0x310 [vmw_balloon] [ 487.141610] ? process_one_work+0x298/0x5e0 [ 487.143053] worker_thread+0x41/0x400 [ 487.144389] kthread+0x12b/0x150 [ 487.145582] ? process_one_work+0x5e0/0x5e0 [ 487.146937] ? kthread_create_on_node+0x60/0x60 [ 487.148637] ret_from_fork+0x3a/0x50 Fix it by updating the PageOffline indication only when a 2MB page is enqueued and dequeued. The 4KB pages will be handled correctly by the balloon compaction logic. Fixes: 83a8afa ("vmw_balloon: Compaction support") Cc: David Hildenbrand <[email protected]> Reported-by: Thomas Hellstrom <[email protected]> Signed-off-by: Nadav Amit <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>

Now that 'TCQ_F_CPUSTATS' bit can be cleared, depending on the value of 'TCQ_F_NOLOCK' bit in the parent qdisc, we need to be sure that per-cpu counters are present when 'reset()' is called for pfifo_fast qdiscs. Otherwise, the following script: # tc q a dev lo handle 1: root htb default 100 # tc c a dev lo parent 1: classid 1:100 htb \ > rate 95Mbit ceil 100Mbit burst 64k [...] # tc f a dev lo parent 1: protocol arp basic classid 1:100 [...] # tc q a dev lo parent 1:100 handle 100: pfifo_fast [...] # tc q d dev lo root can generate the following splat: Unable to handle kernel paging request at virtual address dfff2c01bd148000 Mem abort info: ESR = 0x96000004 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 [dfff2c01bd148000] address between user and kernel address ranges Internal error: Oops: 96000004 [#1] SMP [...] pstate: 80000005 (Nzcv daif -PAN -UAO) pc : pfifo_fast_reset+0x280/0x4d8 lr : pfifo_fast_reset+0x21c/0x4d8 sp : ffff800d09676fa0 x29: ffff800d09676fa0 x28: ffff200012ee22e4 x27: dfff200000000000 x26: 0000000000000000 x25: ffff800ca0799958 x24: ffff1001940f332b x23: 0000000000000007 x22: ffff200012ee1ab8 x21: 0000600de8a40000 x20: 0000000000000000 x19: ffff800ca0799900 x18: 0000000000000000 x17: 0000000000000002 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: ffff1001b922e6e2 x11: 1ffff001b922e6e1 x10: 0000000000000000 x9 : 1ffff001b922e6e1 x8 : dfff200000000000 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 1fffe400025dc45c x4 : 1fffe400025dc357 x3 : 00000c01bd148000 x2 : 0000600de8a40000 x1 : 0000000000000007 x0 : 0000600de8a40004 Call trace: pfifo_fast_reset+0x280/0x4d8 qdisc_reset+0x6c/0x370 htb_reset+0x150/0x3b8 [sch_htb] qdisc_reset+0x6c/0x370 dev_deactivate_queue.constprop.5+0xe0/0x1a8 dev_deactivate_many+0xd8/0x908 dev_deactivate+0xe4/0x190 qdisc_graft+0x88c/0xbd0 tc_get_qdisc+0x418/0x8a8 rtnetlink_rcv_msg+0x3a8/0xa78 netlink_rcv_skb+0x18c/0x328 rtnetlink_rcv+0x28/0x38 netlink_unicast+0x3c4/0x538 netlink_sendmsg+0x538/0x9a0 sock_sendmsg+0xac/0xf8 ___sys_sendmsg+0x53c/0x658 __sys_sendmsg+0xc8/0x140 __arm64_sys_sendmsg+0x74/0xa8 el0_svc_handler+0x164/0x468 el0_svc+0x10/0x14 Code: 910012a0 92400801 d343fc03 11000c21 (38fb6863) Fix this by testing the value of 'TCQ_F_CPUSTATS' bit in 'qdisc->flags', before dereferencing 'qdisc->cpu_qstats'. Changes since v1: - coding style improvements, thanks to Stefano Brivio Fixes: 8a53e61 ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too") CC: Paolo Abeni <[email protected]> Reported-by: Li Shuang <[email protected]> Signed-off-by: Davide Caratti <[email protected]> Acked-by: Paolo Abeni <[email protected]> Reviewed-by: Stefano Brivio <[email protected]> Signed-off-by: David S. Miller <[email protected]>

Now that 'TCQ_F_CPUSTATS' bit can be cleared, depending on the value of 'TCQ_F_NOLOCK' bit in the parent qdisc, we can't assume anymore that per-cpu counters are there in the error path of skb_array_produce(). Otherwise, the following splat can be seen: Unable to handle kernel paging request at virtual address 0000600dea430008 Mem abort info: ESR = 0x96000005 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000005 CM = 0, WnR = 0 user pgtable: 64k pages, 48-bit VAs, pgdp = 000000007b97530e [0000600dea430008] pgd=0000000000000000, pud=0000000000000000 Internal error: Oops: 96000005 [#1] SMP [...] pstate: 10000005 (nzcV daif -PAN -UAO) pc : pfifo_fast_enqueue+0x524/0x6e8 lr : pfifo_fast_enqueue+0x46c/0x6e8 sp : ffff800d39376fe0 x29: ffff800d39376fe0 x28: 1ffff001a07d1e40 x27: ffff800d03e8f188 x26: ffff800d03e8f200 x25: 0000000000000062 x24: ffff800d393772f0 x23: 0000000000000000 x22: 0000000000000403 x21: ffff800cca569a00 x20: ffff800d03e8ee00 x19: ffff800cca569a10 x18: 00000000000000bf x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: ffff1001a726edd0 x13: 1fffe4000276a9a4 x12: 0000000000000000 x11: dfff200000000000 x10: ffff800d03e8f1a0 x9 : 0000000000000003 x8 : 0000000000000000 x7 : 00000000f1f1f1f1 x6 : ffff1001a726edea x5 : ffff800cca56a53c x4 : 1ffff001bf9a8003 x3 : 1ffff001bf9a8003 x2 : 1ffff001a07d1dcb x1 : 0000600dea430000 x0 : 0000600dea430008 Process ping (pid: 6067, stack limit = 0x00000000dc0aa557) Call trace: pfifo_fast_enqueue+0x524/0x6e8 htb_enqueue+0x660/0x10e0 [sch_htb] __dev_queue_xmit+0x123c/0x2de0 dev_queue_xmit+0x24/0x30 ip_finish_output2+0xc48/0x1720 ip_finish_output+0x548/0x9d8 ip_output+0x334/0x788 ip_local_out+0x90/0x138 ip_send_skb+0x44/0x1d0 ip_push_pending_frames+0x5c/0x78 raw_sendmsg+0xed8/0x28d0 inet_sendmsg+0xc4/0x5c0 sock_sendmsg+0xac/0x108 __sys_sendto+0x1ac/0x2a0 __arm64_sys_sendto+0xc4/0x138 el0_svc_handler+0x13c/0x298 el0_svc+0x8/0xc Code: f9402e80 d538d081 91002000 8b010000 (885f7c03) Fix this by testing the value of 'TCQ_F_CPUSTATS' bit in 'qdisc->flags', before dereferencing 'qdisc->cpu_qstats'. Fixes: 8a53e61 ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too") CC: Paolo Abeni <[email protected]> CC: Stefano Brivio <[email protected]> Reported-by: Li Shuang <[email protected]> Signed-off-by: Davide Caratti <[email protected]> Acked-by: Paolo Abeni <[email protected]> Signed-off-by: David S. Miller <[email protected]>

Hayes Wang says: ==================== r8152: fix side effect v3: Update the commit message for patch #1. v2: Replace patch #2 with "r8152: remove calling netif_napi_del". v1: The commit 0ee1f47 ("r8152: napi hangup fix after disconnect") add a check to avoid using napi_disable after netif_napi_del. However, the commit ffa9fec ("r8152: set RTL8152_UNPLUG only for real disconnection") let the check useless. Therefore, I revert commit 0ee1f47 ("r8152: napi hangup fix after disconnect") first, and add another patch to fix it. ==================== Signed-off-by: David S. Miller <[email protected]>

LTP testsuite on powerpc results in the below crash: Unable to handle kernel paging request for data at address 0x00000000 Faulting instruction address: 0xc00000000029d800 Oops: Kernel access of bad area, sig: 11 [#1] LE SMP NR_CPUS=2048 NUMA PowerNV ... CPU: 68 PID: 96584 Comm: cat Kdump: loaded Tainted: G W NIP: c00000000029d800 LR: c00000000029dac4 CTR: c0000000001e6ad0 REGS: c0002017fae8ba10 TRAP: 0300 Tainted: G W MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 28022422 XER: 20040000 CFAR: c00000000029d90c DAR: 0000000000000000 DSISR: 40000000 IRQMASK: 0 ... NIP [c00000000029d800] t_probe_next+0x60/0x180 LR [c00000000029dac4] t_mod_start+0x1a4/0x1f0 Call Trace: [c0002017fae8bc90] [c000000000cdbc40] _cond_resched+0x10/0xb0 (unreliable) [c0002017fae8bce0] [c0000000002a15b0] t_start+0xf0/0x1c0 [c0002017fae8bd30] [c0000000004ec2b4] seq_read+0x184/0x640 [c0002017fae8bdd0] [c0000000004a57bc] sys_read+0x10c/0x300 [c0002017fae8be30] [c00000000000b388] system_call+0x5c/0x70 The test (ftrace_set_ftrace_filter.sh) is part of ftrace stress tests and the crash happens when the test does 'cat $TRACING_PATH/set_ftrace_filter'. The address points to the second line below, in t_probe_next(), where filter_hash is dereferenced: hash = iter->probe->ops.func_hash->filter_hash; size = 1 << hash->size_bits; This happens due to a race with register_ftrace_function_probe(). A new ftrace_func_probe is created and added into the func_probes list in trace_array under ftrace_lock. However, before initializing the filter, we drop ftrace_lock, and re-acquire it after acquiring regex_lock. If another process is trying to read set_ftrace_filter, it will be able to acquire ftrace_lock during this window and it will end up seeing a NULL filter_hash. Fix this by just checking for a NULL filter_hash in t_probe_next(). If the filter_hash is NULL, then this probe is just being added and we can simply return from here. Link: http://lkml.kernel.org/r/05e021f757625cbbb006fad41380323dbe4e3b43.1562249521.git.naveen.n.rao@linux.vnet.ibm.com Cc: [email protected] Fixes: 7b60f3d ("ftrace: Dynamically create the probe ftrace_ops for the trace_array") Signed-off-by: Naveen N. Rao <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>

If a request_key authentication token key gets revoked, there's a window in which request_key_auth_describe() can see it with a NULL payload - but it makes no check for this and something like the following oops may occur: BUG: Kernel NULL pointer dereference at 0x00000038 Faulting instruction address: 0xc0000000004ddf30 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [...] request_key_auth_describe+0x90/0xd0 LR [...] request_key_auth_describe+0x54/0xd0 Call Trace: [...] request_key_auth_describe+0x54/0xd0 (unreliable) [...] proc_keys_show+0x308/0x4c0 [...] seq_read+0x3d0/0x540 [...] proc_reg_read+0x90/0x110 [...] __vfs_read+0x3c/0x70 [...] vfs_read+0xb4/0x1b0 [...] ksys_read+0x7c/0x130 [...] system_call+0x5c/0x70 Fix this by checking for a NULL pointer when describing such a key. Also make the read routine check for a NULL pointer to be on the safe side. [DH: Modified to not take already-held rcu lock and modified to also check in the read routine] Fixes: 04c567d ("[PATCH] Keys: Fix race between two instantiators of a key") Reported-by: Sachin Sant <[email protected]> Signed-off-by: Hillf Danton <[email protected]> Signed-off-by: David Howells <[email protected]> Tested-by: Sachin Sant <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

This patch fixes the lock inversion complaint: ============================================ WARNING: possible recursive locking detected 5.3.0-rc7-dbg+ #1 Not tainted -------------------------------------------- kworker/u16:6/171 is trying to acquire lock: 00000000035c6e6c (&id_priv->handler_mutex){+.+.}, at: rdma_destroy_id+0x78/0x4a0 [rdma_cm] but task is already holding lock: 00000000bc7c307d (&id_priv->handler_mutex){+.+.}, at: iw_conn_req_handler+0x151/0x680 [rdma_cm] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&id_priv->handler_mutex); lock(&id_priv->handler_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by kworker/u16:6/171: #0: 00000000e2eaa773 ((wq_completion)iw_cm_wq){+.+.}, at: process_one_work+0x472/0xac0 #1: 000000001efd357b ((work_completion)(&work->work)#3){+.+.}, at: process_one_work+0x476/0xac0 #2: 00000000bc7c307d (&id_priv->handler_mutex){+.+.}, at: iw_conn_req_handler+0x151/0x680 [rdma_cm] stack backtrace: CPU: 3 PID: 171 Comm: kworker/u16:6 Not tainted 5.3.0-rc7-dbg+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 Workqueue: iw_cm_wq cm_work_handler [iw_cm] Call Trace: dump_stack+0x8a/0xd6 __lock_acquire.cold+0xe1/0x24d lock_acquire+0x106/0x240 __mutex_lock+0x12e/0xcb0 mutex_lock_nested+0x1f/0x30 rdma_destroy_id+0x78/0x4a0 [rdma_cm] iw_conn_req_handler+0x5c9/0x680 [rdma_cm] cm_work_handler+0xe62/0x1100 [iw_cm] process_one_work+0x56d/0xac0 worker_thread+0x7a/0x5d0 kthread+0x1bc/0x210 ret_from_fork+0x24/0x30 This is not a bug as there are actually two lock classes here. Link: https://lore.kernel.org/r/[email protected] Fixes: de910bd ("RDMA/cma: Simplify locking needed for serialization of callbacks") Signed-off-by: Bart Van Assche <[email protected]> Reviewed-by: Jason Gunthorpe <[email protected]> Signed-off-by: Jason Gunthorpe <[email protected]>

A user reported a lockdep splat ====================================================== WARNING: possible circular locking dependency detected 5.2.11-gentoo #2 Not tainted ------------------------------------------------------ kswapd0/711 is trying to acquire lock: 000000007777a663 (sb_internal){.+.+}, at: start_transaction+0x3a8/0x500 but task is already holding lock: 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}: kmem_cache_alloc+0x1f/0x1c0 btrfs_alloc_inode+0x1f/0x260 alloc_inode+0x16/0xa0 new_inode+0xe/0xb0 btrfs_new_inode+0x70/0x610 btrfs_symlink+0xd0/0x420 vfs_symlink+0x9c/0x100 do_symlinkat+0x66/0xe0 do_syscall_64+0x55/0x1c0 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (sb_internal){.+.+}: __sb_start_write+0xf6/0x150 start_transaction+0x3a8/0x500 btrfs_commit_inode_delayed_inode+0x59/0x110 btrfs_evict_inode+0x19e/0x4c0 evict+0xbc/0x1f0 inode_lru_isolate+0x113/0x190 __list_lru_walk_one.isra.4+0x5c/0x100 list_lru_walk_one+0x32/0x50 prune_icache_sb+0x36/0x80 super_cache_scan+0x14a/0x1d0 do_shrink_slab+0x131/0x320 shrink_node+0xf7/0x380 balance_pgdat+0x2d5/0x640 kswapd+0x2ba/0x5e0 kthread+0x147/0x160 ret_from_fork+0x24/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(sb_internal); lock(fs_reclaim); lock(sb_internal); *** DEADLOCK *** 3 locks held by kswapd0/711: #0: 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30 #1: 000000004a5100f8 (shrinker_rwsem){++++}, at: shrink_node+0x9a/0x380 #2: 00000000f956fa46 (&type->s_umount_key#30){++++}, at: super_cache_scan+0x35/0x1d0 stack backtrace: CPU: 7 PID: 711 Comm: kswapd0 Not tainted 5.2.11-gentoo #2 Hardware name: Dell Inc. Precision Tower 3620/0MWYPT, BIOS 2.4.2 09/29/2017 Call Trace: dump_stack+0x85/0xc7 print_circular_bug.cold.40+0x1d9/0x235 __lock_acquire+0x18b1/0x1f00 lock_acquire+0xa6/0x170 ? start_transaction+0x3a8/0x500 __sb_start_write+0xf6/0x150 ? start_transaction+0x3a8/0x500 start_transaction+0x3a8/0x500 btrfs_commit_inode_delayed_inode+0x59/0x110 btrfs_evict_inode+0x19e/0x4c0 ? var_wake_function+0x20/0x20 evict+0xbc/0x1f0 inode_lru_isolate+0x113/0x190 ? discard_new_inode+0xc0/0xc0 __list_lru_walk_one.isra.4+0x5c/0x100 ? discard_new_inode+0xc0/0xc0 list_lru_walk_one+0x32/0x50 prune_icache_sb+0x36/0x80 super_cache_scan+0x14a/0x1d0 do_shrink_slab+0x131/0x320 shrink_node+0xf7/0x380 balance_pgdat+0x2d5/0x640 kswapd+0x2ba/0x5e0 ? __wake_up_common_lock+0x90/0x90 kthread+0x147/0x160 ? balance_pgdat+0x640/0x640 ? __kthread_create_on_node+0x160/0x160 ret_from_fork+0x24/0x30 This is because btrfs_new_inode() calls new_inode() under the transaction. We could probably move the new_inode() outside of this but for now just wrap it in memalloc_nofs_save(). Reported-by: Zdenek Sojka <[email protected]> Fixes: 712e36c ("btrfs: use GFP_KERNEL in btrfs_alloc_inode") CC: [email protected] # 4.16+ Reviewed-by: Filipe Manana <[email protected]> Signed-off-by: Josef Bacik <[email protected]> Reviewed-by: David Sterba <[email protected]> Signed-off-by: David Sterba <[email protected]>

Call uart_unregister_driver() conditionally instead of unconditionally, only if it has been previously registered. This uses driver.state, just as the sh-sci.c driver does. Fixes this null pointer dereference in tty_unregister_driver(), since the 'driver' argument is null: general protection fault: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:tty_unregister_driver+0x25/0x1d0 Fixes: 238b872 ("[PATCH] serial uartlite driver") Signed-off-by: Randy Dunlap <[email protected]> Cc: stable <[email protected]> Cc: Peter Korsgaard <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>

When using virtual engines, the rq->engine is not stable until we hold the engine->active.lock (as the virtual engine may be exchanged with the sibling). Since commit 22b7a42 ("drm/i915/execlists: Preempt-to-busy") we may retire a request concurrently with resubmitting it to HW, we need to be extra careful to verify we are holding the correct lock for the request's active list. This is similar to the issue we saw with rescheduling the virtual requests, see sched_lock_engine(). Or else: <4> [876.736126] list_add corruption. prev->next should be next (ffff8883f931a1f8), but was dead000000000100. (prev=ffff888361ffa610). <4> [876.736136] WARNING: CPU: 2 PID: 21 at lib/list_debug.c:28 __list_add_valid+0x4d/0x70 <4> [876.736137] Modules linked in: i915(+) amdgpu gpu_sched ttm vgem snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic mei_hdcp x86_pkg_temp_thermal coretemp crct10dif_pclmul crc32_pclmul snd_intel_nhlt snd_hda_codec snd_hwdep snd_hda_core ghash_clmulni_intel e1000e cdc_ether usbnet mii snd_pcm ptp pps_core mei_me mei prime_numbers btusb btrtl btbcm btintel bluetooth ecdh_generic ecc [last unloaded: i915] <4> [876.736154] CPU: 2 PID: 21 Comm: ksoftirqd/2 Tainted: G U 5.3.0-CI-CI_DRM_6898+ #1 <4> [876.736156] Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3183.A00.1905020411 05/02/2019 <4> [876.736157] RIP: 0010:__list_add_valid+0x4d/0x70 <4> [876.736159] Code: c3 48 89 d1 48 c7 c7 20 33 0e 82 48 89 c2 e8 4a 4a bc ff 0f 0b 31 c0 c3 48 89 c1 4c 89 c6 48 c7 c7 70 33 0e 82 e8 33 4a bc ff <0f> 0b 31 c0 c3 48 89 f2 4c 89 c1 48 89 fe 48 c7 c7 c0 33 0e 82 e8 <4> [876.736160] RSP: 0018:ffffc9000018bd30 EFLAGS: 00010082 <4> [876.736162] RAX: 0000000000000000 RBX: ffff888361ffc840 RCX: 0000000000000104 <4> [876.736163] RDX: 0000000080000104 RSI: 0000000000000000 RDI: 00000000ffffffff <4> [876.736164] RBP: ffffc9000018bd68 R08: 0000000000000000 R09: 0000000000000001 <4> [876.736165] R10: 00000000aed95de3 R11: 000000007fe927eb R12: ffff888361ffca10 <4> [876.736166] R13: ffff888361ffa610 R14: ffff888361ffc880 R15: ffff8883f931a1f8 <4> [876.736168] FS: 0000000000000000(0000) GS:ffff88849fd00000(0000) knlGS:0000000000000000 <4> [876.736169] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4> [876.736170] CR2: 00007f093a9173c0 CR3: 00000003bba08005 CR4: 0000000000760ee0 <4> [876.736171] PKRU: 55555554 <4> [876.736172] Call Trace: <4> [876.736226] __i915_request_submit+0x152/0x370 [i915] <4> [876.736263] __execlists_submission_tasklet+0x6da/0x1f50 [i915] <4> [876.736293] ? execlists_submission_tasklet+0x29/0x50 [i915] <4> [876.736321] execlists_submission_tasklet+0x34/0x50 [i915] <4> [876.736325] tasklet_action_common.isra.5+0x47/0xb0 <4> [876.736328] __do_softirq+0xd8/0x4ae <4> [876.736332] ? smpboot_thread_fn+0x23/0x280 <4> [876.736334] ? smpboot_thread_fn+0x6b/0x280 <4> [876.736336] run_ksoftirqd+0x2b/0x50 <4> [876.736338] smpboot_thread_fn+0x1d3/0x280 <4> [876.736341] ? sort_range+0x20/0x20 <4> [876.736343] kthread+0x119/0x130 <4> [876.736345] ? kthread_park+0xa0/0xa0 <4> [876.736347] ret_from_fork+0x24/0x50 <4> [876.736353] irq event stamp: 2290145 <4> [876.736356] hardirqs last enabled at (2290144): [<ffffffff8123cde8>] __slab_free+0x3e8/0x500 <4> [876.736358] hardirqs last disabled at (2290145): [<ffffffff819cfb4d>] _raw_spin_lock_irqsave+0xd/0x50 <4> [876.736360] softirqs last enabled at (2290114): [<ffffffff81c0033e>] __do_softirq+0x33e/0x4ae <4> [876.736361] softirqs last disabled at (2290119): [<ffffffff810b815b>] run_ksoftirqd+0x2b/0x50 <4> [876.736363] WARNING: CPU: 2 PID: 21 at lib/list_debug.c:28 __list_add_valid+0x4d/0x70 <4> [876.736364] ---[ end trace 3e58d6c7356c65bf ]--- <4> [876.736406] ------------[ cut here ]------------ <4> [876.736415] list_del corruption. prev->next should be ffff888361ffca10, but was ffff88840ac2c730 <4> [876.736421] WARNING: CPU: 2 PID: 5490 at lib/list_debug.c:53 __list_del_entry_valid+0x79/0x90 <4> [876.736422] Modules linked in: i915(+) amdgpu gpu_sched ttm vgem snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic mei_hdcp x86_pkg_temp_thermal coretemp crct10dif_pclmul crc32_pclmul snd_intel_nhlt snd_hda_codec snd_hwdep snd_hda_core ghash_clmulni_intel e1000e cdc_ether usbnet mii snd_pcm ptp pps_core mei_me mei prime_numbers btusb btrtl btbcm btintel bluetooth ecdh_generic ecc [last unloaded: i915] <4> [876.736433] CPU: 2 PID: 5490 Comm: i915_selftest Tainted: G U W 5.3.0-CI-CI_DRM_6898+ #1 <4> [876.736435] Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3183.A00.1905020411 05/02/2019 <4> [876.736436] RIP: 0010:__list_del_entry_valid+0x79/0x90 <4> [876.736438] Code: 0b 31 c0 c3 48 89 fe 48 c7 c7 30 34 0e 82 e8 ae 49 bc ff 0f 0b 31 c0 c3 48 89 f2 48 89 fe 48 c7 c7 68 34 0e 82 e8 97 49 bc ff <0f> 0b 31 c0 c3 48 c7 c7 a8 34 0e 82 e8 86 49 bc ff 0f 0b 31 c0 c3 <4> [876.736439] RSP: 0018:ffffc900003ef758 EFLAGS: 00010086 <4> [876.736440] RAX: 0000000000000000 RBX: ffff888361ffc840 RCX: 0000000000000002 <4> [876.736442] RDX: 0000000080000002 RSI: 0000000000000000 RDI: 00000000ffffffff <4> [876.736443] RBP: ffffc900003ef780 R08: 0000000000000000 R09: 0000000000000001 <4> [876.736444] R10: 000000001418e4b7 R11: 000000007f0ea93b R12: ffff888361ffcab8 <4> [876.736445] R13: ffff88843b6d0000 R14: 000000000000217c R15: 0000000000000001 <4> [876.736447] FS: 00007f4e6f255240(0000) GS:ffff88849fd00000(0000) knlGS:0000000000000000 <4> [876.736448] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4> [876.736449] CR2: 00007f093a9173c0 CR3: 00000003bba08005 CR4: 0000000000760ee0 <4> [876.736450] PKRU: 55555554 <4> [876.736451] Call Trace: <4> [876.736488] i915_request_retire+0x224/0x8e0 [i915] <4> [876.736521] i915_request_create+0x4b/0x1b0 [i915] <4> [876.736550] nop_virtual_engine+0x230/0x4d0 [i915] Fixes: 22b7a42 ("drm/i915/execlists: Preempt-to-busy") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111695 Signed-off-by: Chris Wilson <[email protected]> Cc: Mika Kuoppala <[email protected]> Cc: Tvrtko Ursulin <[email protected]> Cc: Matthew Auld <[email protected]> Reviewed-by: Tvrtko Ursulin <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] (cherry picked from commit 37fa0de) Signed-off-by: Rodrigo Vivi <[email protected]>

Calling 'panic()' on a kernel with CONFIG_PREEMPT=y can leave the calling CPU in an infinite loop, but with interrupts and preemption enabled. From this state, userspace can continue to be scheduled, despite the system being "dead" as far as the kernel is concerned. This is easily reproducible on arm64 when booting with "nosmp" on the command line; a couple of shell scripts print out a periodic "Ping" message whilst another triggers a crash by writing to /proc/sysrq-trigger: | sysrq: Trigger a crash | Kernel panic - not syncing: sysrq triggered crash | CPU: 0 PID: 1 Comm: init Not tainted 5.2.15 #1 | Hardware name: linux,dummy-virt (DT) | Call trace: | dump_backtrace+0x0/0x148 | show_stack+0x14/0x20 | dump_stack+0xa0/0xc4 | panic+0x140/0x32c | sysrq_handle_reboot+0x0/0x20 | __handle_sysrq+0x124/0x190 | write_sysrq_trigger+0x64/0x88 | proc_reg_write+0x60/0xa8 | __vfs_write+0x18/0x40 | vfs_write+0xa4/0x1b8 | ksys_write+0x64/0xf0 | __arm64_sys_write+0x14/0x20 | el0_svc_common.constprop.0+0xb0/0x168 | el0_svc_handler+0x28/0x78 | el0_svc+0x8/0xc | Kernel Offset: disabled | CPU features: 0x0002,24002004 | Memory Limit: none | ---[ end Kernel panic - not syncing: sysrq triggered crash ]--- | Ping 2! | Ping 1! | Ping 1! | Ping 2! The issue can also be triggered on x86 kernels if CONFIG_SMP=n, otherwise local interrupts are disabled in 'smp_send_stop()'. Disable preemption in 'panic()' before re-enabling interrupts. Link: http://lkml.kernel.org/r/[email protected] Link: https://lore.kernel.org/r/BX1W47JXPMR8.58IYW53H6M5N@dragonstone Signed-off-by: Will Deacon <[email protected]> Reported-by: Xogium <[email protected]> Reviewed-by: Kees Cook <[email protected]> Cc: Russell King <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Petr Mladek <[email protected]> Cc: Feng Tang <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

@done

finish_writeback_work() reads @done->waitq after decrementing @done->cnt. However, once @done->cnt reaches zero, @done may be freed (from stack) at any moment and @done->waitq can contain something unrelated by the time finish_writeback_work() tries to read it. This led to the following crash. "BUG: kernel NULL pointer dereference, address: 0000000000000002" #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP DEBUG_PAGEALLOC CPU: 40 PID: 555153 Comm: kworker/u98:50 Kdump: loaded Not tainted ... Workqueue: writeback wb_workfn (flush-btrfs-1) RIP: 0010:_raw_spin_lock_irqsave+0x10/0x30 Code: 48 89 d8 5b c3 e8 50 db 6b ff eb f4 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 9c 5b fa 31 c0 ba 01 00 00 00 <f0> 0f b1 17 75 05 48 89 d8 5b c3 89 c6 e8 fe ca 6b ff eb f2 66 90 RSP: 0018:ffffc90049b27d98 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000246 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000003 RDI: 0000000000000002 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 R10: ffff889fff407600 R11: ffff88ba9395d740 R12: 000000000000e300 R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88bfdfa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000002 CR3: 0000000002409005 CR4: 00000000001606e0 Call Trace: __wake_up_common_lock+0x63/0xc0 wb_workfn+0xd2/0x3e0 process_one_work+0x1f5/0x3f0 worker_thread+0x2d/0x3d0 kthread+0x111/0x130 ret_from_fork+0x1f/0x30 Fix it by reading and caching @done->waitq before decrementing @done->cnt. Link: http://lkml.kernel.org/r/[email protected] Fixes: 5b9cce4 ("writeback: Generalize and expose wb_completion") Signed-off-by: Tejun Heo <[email protected]> Debugged-by: Chris Mason <[email protected]> Reviewed-by: Jens Axboe <[email protected]> Cc: Jan Kara <[email protected]> Cc: <[email protected]> [5.2+] Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

…not disabled In kdump kernel, memcg usually is disabled with 'cgroup_disable=memory' for saving memory. Now kdump kernel will always panic when dump vmcore to local disk: BUG: kernel NULL pointer dereference, address: 0000000000000ab8 Oops: 0000 [#1] SMP NOPTI CPU: 0 PID: 598 Comm: makedumpfile Not tainted 5.3.0+ linux-kernel-labs#26 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 10/02/2018 RIP: 0010:mem_cgroup_track_foreign_dirty_slowpath+0x38/0x140 Call Trace: __set_page_dirty+0x52/0xc0 iomap_set_page_dirty+0x50/0x90 iomap_write_end+0x6e/0x270 iomap_write_actor+0xce/0x170 iomap_apply+0xba/0x11e iomap_file_buffered_write+0x62/0x90 xfs_file_buffered_aio_write+0xca/0x320 [xfs] new_sync_write+0x12d/0x1d0 vfs_write+0xa5/0x1a0 ksys_write+0x59/0xd0 do_syscall_64+0x59/0x1e0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 And this will corrupt the 1st kernel too with 'cgroup_disable=memory'. Via the trace and with debugging, it is pointing to commit 97b2782 ("writeback, memcg: Implement foreign dirty flushing") which introduced this regression. Disabling memcg causes the null pointer dereference at uninitialized data in function mem_cgroup_track_foreign_dirty_slowpath(). Fix it by returning directly if memcg is disabled, but not trying to record the foreign writebacks with dirty pages. Link: http://lkml.kernel.org/r/20190924141928.GD31919@MiWiFi-R3L-srv Fixes: 97b2782 ("writeback, memcg: Implement foreign dirty flushing") Signed-off-by: Baoquan He <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Jan Kara <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Jens Axboe <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

syzbot got a NULL dereference in bond_update_slave_arr() [1], happening after a failure to allocate bond->slave_arr A workqueue (bond_slave_arr_handler) is supposed to retry the allocation later, but if the slave is removed before the workqueue had a chance to complete, bond->slave_arr can still be NULL. [1] Failed to build slave-array. kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN PTI Modules linked in: Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:bond_update_slave_arr.cold+0xc6/0x198 drivers/net/bonding/bond_main.c:4039 RSP: 0018:ffff88018fe33678 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000290b000 RDX: 0000000000000000 RSI: ffffffff82b63037 RDI: ffff88019745ea20 RBP: ffff88018fe33760 R08: ffff880170754280 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff88019745ea00 R14: 0000000000000000 R15: ffff88018fe338b0 FS: 00007febd837d700(0000) GS:ffff8801dad00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004540a0 CR3: 00000001c242e005 CR4: 00000000001626f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: [<ffffffff82b5b45e>] __bond_release_one+0x43e/0x500 drivers/net/bonding/bond_main.c:1923 [<ffffffff82b5b966>] bond_release drivers/net/bonding/bond_main.c:2039 [inline] [<ffffffff82b5b966>] bond_do_ioctl+0x416/0x870 drivers/net/bonding/bond_main.c:3562 [<ffffffff83ae25f4>] dev_ifsioc+0x6f4/0x940 net/core/dev_ioctl.c:328 [<ffffffff83ae2e58>] dev_ioctl+0x1b8/0xc70 net/core/dev_ioctl.c:495 [<ffffffff83995ffd>] sock_do_ioctl+0x1bd/0x300 net/socket.c:1088 [<ffffffff83996a80>] sock_ioctl+0x300/0x5d0 net/socket.c:1196 [<ffffffff81b124db>] vfs_ioctl fs/ioctl.c:47 [inline] [<ffffffff81b124db>] file_ioctl fs/ioctl.c:501 [inline] [<ffffffff81b124db>] do_vfs_ioctl+0xacb/0x1300 fs/ioctl.c:688 [<ffffffff81b12dc6>] SYSC_ioctl fs/ioctl.c:705 [inline] [<ffffffff81b12dc6>] SyS_ioctl+0xb6/0xe0 fs/ioctl.c:696 [<ffffffff8101ccc8>] do_syscall_64+0x528/0x770 arch/x86/entry/common.c:305 [<ffffffff84400091>] entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: ee63771 ("bonding: Simplify the xmit function for modes that use xmit_hash") Signed-off-by: Eric Dumazet <[email protected]> Reported-by: syzbot <[email protected]> Cc: Mahesh Bandewar <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]>

A customer reported the following softlockup: [899688.160002] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [test.sh:16464] [899688.160002] CPU: 0 PID: 16464 Comm: test.sh Not tainted 4.12.14-6.23-azure #1 SLE12-SP4 [899688.160002] RIP: 0010:up_write+0x1a/0x30 [899688.160002] Kernel panic - not syncing: softlockup: hung tasks [899688.160002] RIP: 0010:up_write+0x1a/0x30 [899688.160002] RSP: 0018:ffffa86784d4fde8 EFLAGS: 00000257 ORIG_RAX: ffffffffffffff12 [899688.160002] RAX: ffffffff970fea00 RBX: 0000000000000001 RCX: 0000000000000000 [899688.160002] RDX: ffffffff00000001 RSI: 0000000000000080 RDI: ffffffff970fea00 [899688.160002] RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000 [899688.160002] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b59014720d8 [899688.160002] R13: ffff8b59014720c0 R14: ffff8b5901471090 R15: ffff8b5901470000 [899688.160002] tracing_read_pipe+0x336/0x3c0 [899688.160002] __vfs_read+0x26/0x140 [899688.160002] vfs_read+0x87/0x130 [899688.160002] SyS_read+0x42/0x90 [899688.160002] do_syscall_64+0x74/0x160 It caught the process in the middle of trace_access_unlock(). There is no loop. So, it must be looping in the caller tracing_read_pipe() via the "waitagain" label. Crashdump analyze uncovered that iter->seq was completely zeroed at this point, including iter->seq.seq.size. It means that print_trace_line() was never able to print anything and there was no forward progress. The culprit seems to be in the code: /* reset all but tr, trace, and overruns */ memset(&iter->seq, 0, sizeof(struct trace_iterator) - offsetof(struct trace_iterator, seq)); It was added by the commit 53d0aa7 ("ftrace: add logic to record overruns"). It was v2.6.27-rc1. It was the time when iter->seq looked like: struct trace_seq { unsigned char buffer[PAGE_SIZE]; unsigned int len; }; There was no "size" variable and zeroing was perfectly fine. The solution is to reinitialize the structure after or without zeroing. Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Petr Mladek <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>

A long time ago we fixed a similar deadlock in show_slab_objects() [1]. However, it is apparently due to the commits like 01fb58b ("slab: remove synchronous synchronize_sched() from memcg cache deactivation path") and 03afc0e ("slab: get_online_mems for kmem_cache_{create,destroy,shrink}"), this kind of deadlock is back by just reading files in /sys/kernel/slab which will generate a lockdep splat below. Since the "mem_hotplug_lock" here is only to obtain a stable online node mask while racing with NUMA node hotplug, in the worst case, the results may me miscalculated while doing NUMA node hotplug, but they shall be corrected by later reads of the same files. WARNING: possible circular locking dependency detected ------------------------------------------------------ cat/5224 is trying to acquire lock: ffff900012ac3120 (mem_hotplug_lock.rw_sem){++++}, at: show_slab_objects+0x94/0x3a8 but task is already holding lock: b8ff009693eee398 (kn->count#45){++++}, at: kernfs_seq_start+0x44/0xf0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (kn->count#45){++++}: lock_acquire+0x31c/0x360 __kernfs_remove+0x290/0x490 kernfs_remove+0x30/0x44 sysfs_remove_dir+0x70/0x88 kobject_del+0x50/0xb0 sysfs_slab_unlink+0x2c/0x38 shutdown_cache+0xa0/0xf0 kmemcg_cache_shutdown_fn+0x1c/0x34 kmemcg_workfn+0x44/0x64 process_one_work+0x4f4/0x950 worker_thread+0x390/0x4bc kthread+0x1cc/0x1e8 ret_from_fork+0x10/0x18 -> #1 (slab_mutex){+.+.}: lock_acquire+0x31c/0x360 __mutex_lock_common+0x16c/0xf78 mutex_lock_nested+0x40/0x50 memcg_create_kmem_cache+0x38/0x16c memcg_kmem_cache_create_func+0x3c/0x70 process_one_work+0x4f4/0x950 worker_thread+0x390/0x4bc kthread+0x1cc/0x1e8 ret_from_fork+0x10/0x18 -> #0 (mem_hotplug_lock.rw_sem){++++}: validate_chain+0xd10/0x2bcc __lock_acquire+0x7f4/0xb8c lock_acquire+0x31c/0x360 get_online_mems+0x54/0x150 show_slab_objects+0x94/0x3a8 total_objects_show+0x28/0x34 slab_attr_show+0x38/0x54 sysfs_kf_seq_show+0x198/0x2d4 kernfs_seq_show+0xa4/0xcc seq_read+0x30c/0x8a8 kernfs_fop_read+0xa8/0x314 __vfs_read+0x88/0x20c vfs_read+0xd8/0x10c ksys_read+0xb0/0x120 __arm64_sys_read+0x54/0x88 el0_svc_handler+0x170/0x240 el0_svc+0x8/0xc other info that might help us debug this: Chain exists of: mem_hotplug_lock.rw_sem --> slab_mutex --> kn->count#45 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(kn->count#45); lock(slab_mutex); lock(kn->count#45); lock(mem_hotplug_lock.rw_sem); *** DEADLOCK *** 3 locks held by cat/5224: #0: 9eff00095b14b2a0 (&p->lock){+.+.}, at: seq_read+0x4c/0x8a8 #1: 0eff008997041480 (&of->mutex){+.+.}, at: kernfs_seq_start+0x34/0xf0 #2: b8ff009693eee398 (kn->count#45){++++}, at: kernfs_seq_start+0x44/0xf0 stack backtrace: Call trace: dump_backtrace+0x0/0x248 show_stack+0x20/0x2c dump_stack+0xd0/0x140 print_circular_bug+0x368/0x380 check_noncircular+0x248/0x250 validate_chain+0xd10/0x2bcc __lock_acquire+0x7f4/0xb8c lock_acquire+0x31c/0x360 get_online_mems+0x54/0x150 show_slab_objects+0x94/0x3a8 total_objects_show+0x28/0x34 slab_attr_show+0x38/0x54 sysfs_kf_seq_show+0x198/0x2d4 kernfs_seq_show+0xa4/0xcc seq_read+0x30c/0x8a8 kernfs_fop_read+0xa8/0x314 __vfs_read+0x88/0x20c vfs_read+0xd8/0x10c ksys_read+0xb0/0x120 __arm64_sys_read+0x54/0x88 el0_svc_handler+0x170/0x240 el0_svc+0x8/0xc I think it is important to mention that this doesn't expose the show_slab_objects to use-after-free. There is only a single path that might really race here and that is the slab hotplug notifier callback __kmem_cache_shrink (via slab_mem_going_offline_callback) but that path doesn't really destroy kmem_cache_node data structures. [1] http://lkml.iu.edu/hypermail/linux/kernel/1101.0/02850.html [[email protected]: add comment explaining why we don't need mem_hotplug_lock] Link: http://lkml.kernel.org/r/[email protected] Fixes: 01fb58b ("slab: remove synchronous synchronize_sched() from memcg cache deactivation path") Fixes: 03afc0e ("slab: get_online_mems for kmem_cache_{create,destroy,shrink}") Signed-off-by: Qian Cai <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Christoph Lameter <[email protected]> Cc: Pekka Enberg <[email protected]> Cc: David Rientjes <[email protected]> Cc: Joonsoo Kim <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Vladimir Davydov <[email protected]> Cc: Roman Gushchin <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

Connecting a vCPU to a XIVE KVM device means establishing a 1:1 association between a vCPU id and the offset (VP id) of a VP structure within a fixed size block of VPs. We currently try to enforce the 1:1 relationship by checking that a vCPU with the same id isn't already connected. This is good but unfortunately not enough because we don't map VP ids to raw vCPU ids but to packed vCPU ids, and the packing function kvmppc_pack_vcpu_id() isn't bijective by design. We got away with it because QEMU passes vCPU ids that fit well in the packing pattern. But nothing prevents userspace to come up with a forged vCPU id resulting in a packed id collision which causes the KVM device to associate two vCPUs to the same VP. This greatly confuses the irq layer and ultimately crashes the kernel, as shown below. Example: a guest with 1 guest thread per core, a core stride of 8 and 300 vCPUs has vCPU ids 0,8,16...2392. If QEMU is patched to inject at some point an invalid vCPU id 348, which is the packed version of itself and 2392, we get: genirq: Flags mismatch irq 199. 00010000 (kvm-2-2392) vs. 00010000 (kvm-2-348) CPU: 24 PID: 88176 Comm: qemu-system-ppc Not tainted 5.3.0-xive-nr-servers-5.3-gku+ linux-kernel-labs#38 Call Trace: [c000003f7f9937e0] [c000000000c0110c] dump_stack+0xb0/0xf4 (unreliable) [c000003f7f993820] [c0000000001cb480] __setup_irq+0xa70/0xad0 [c000003f7f9938d0] [c0000000001cb75c] request_threaded_irq+0x13c/0x260 [c000003f7f993940] [c00800000d44e7ac] kvmppc_xive_attach_escalation+0x104/0x270 [kvm] [c000003f7f9939d0] [c00800000d45013c] kvmppc_xive_connect_vcpu+0x424/0x620 [kvm] [c000003f7f993ac0] [c00800000d444428] kvm_arch_vcpu_ioctl+0x260/0x448 [kvm] [c000003f7f993b90] [c00800000d43593c] kvm_vcpu_ioctl+0x154/0x7c8 [kvm] [c000003f7f993d00] [c0000000004840f0] do_vfs_ioctl+0xe0/0xc30 [c000003f7f993db0] [c000000000484d44] ksys_ioctl+0x104/0x120 [c000003f7f993e00] [c000000000484d88] sys_ioctl+0x28/0x80 [c000003f7f993e20] [c00000000000b278] system_call+0x5c/0x68 xive-kvm: Failed to request escalation interrupt for queue 0 of VCPU 2392 ------------[ cut here ]------------ remove_proc_entry: removing non-empty directory 'irq/199', leaking at least 'kvm-2-348' WARNING: CPU: 24 PID: 88176 at /home/greg/Work/linux/kernel-kvm-ppc/fs/proc/generic.c:684 remove_proc_entry+0x1ec/0x200 Modules linked in: kvm_hv kvm dm_mod vhost_net vhost tap xt_CHECKSUM iptable_mangle xt_MASQUERADE iptable_nat nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ipt_REJECT nf_reject_ipv4 tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter squashfs loop fuse i2c_dev sg ofpart ocxl powernv_flash at24 xts mtd uio_pdrv_genirq vmx_crypto opal_prd ipmi_powernv uio ipmi_devintf ipmi_msghandler ibmpowernv ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables ext4 mbcache jbd2 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq libcrc32c raid1 raid0 linear sd_mod ast i2c_algo_bit drm_vram_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm ahci libahci libata tg3 drm_panel_orientation_quirks [last unloaded: kvm] CPU: 24 PID: 88176 Comm: qemu-system-ppc Not tainted 5.3.0-xive-nr-servers-5.3-gku+ linux-kernel-labs#38 NIP: c00000000053b0cc LR: c00000000053b0c8 CTR: c0000000000ba3b0 REGS: c000003f7f9934b0 TRAP: 0700 Not tainted (5.3.0-xive-nr-servers-5.3-gku+) MSR: 9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 48228222 XER: 20040000 CFAR: c000000000131a50 IRQMASK: 0 GPR00: c00000000053b0c8 c000003f7f993740 c0000000015ec500 0000000000000057 GPR04: 0000000000000001 0000000000000000 000049fb98484262 0000000000001bcf GPR08: 0000000000000007 0000000000000007 0000000000000001 9000000000001033 GPR12: 0000000000008000 c000003ffffeb800 0000000000000000 000000012f4ce5a1 GPR16: 000000012ef5a0c8 0000000000000000 000000012f113bb0 0000000000000000 GPR20: 000000012f45d918 c000003f863758b0 c000003f86375870 0000000000000006 GPR24: c000003f86375a30 0000000000000007 c0002039373d9020 c0000000014c4a48 GPR28: 0000000000000001 c000003fe62a4f6b c00020394b2e9fab c000003fe62a4ec0 NIP [c00000000053b0cc] remove_proc_entry+0x1ec/0x200 LR [c00000000053b0c8] remove_proc_entry+0x1e8/0x200 Call Trace: [c000003f7f993740] [c00000000053b0c8] remove_proc_entry+0x1e8/0x200 (unreliable) [c000003f7f9937e0] [c0000000001d3654] unregister_irq_proc+0x114/0x150 [c000003f7f993880] [c0000000001c6284] free_desc+0x54/0xb0 [c000003f7f9938c0] [c0000000001c65ec] irq_free_descs+0xac/0x100 [c000003f7f993910] [c0000000001d1ff8] irq_dispose_mapping+0x68/0x80 [c000003f7f993940] [c00800000d44e8a4] kvmppc_xive_attach_escalation+0x1fc/0x270 [kvm] [c000003f7f9939d0] [c00800000d45013c] kvmppc_xive_connect_vcpu+0x424/0x620 [kvm] [c000003f7f993ac0] [c00800000d444428] kvm_arch_vcpu_ioctl+0x260/0x448 [kvm] [c000003f7f993b90] [c00800000d43593c] kvm_vcpu_ioctl+0x154/0x7c8 [kvm] [c000003f7f993d00] [c0000000004840f0] do_vfs_ioctl+0xe0/0xc30 [c000003f7f993db0] [c000000000484d44] ksys_ioctl+0x104/0x120 [c000003f7f993e00] [c000000000484d88] sys_ioctl+0x28/0x80 [c000003f7f993e20] [c00000000000b278] system_call+0x5c/0x68 Instruction dump: 2c230000 41820008 3923ff78 e8e900a0 3c82ff69 3c62ff8d 7fa6eb78 7fc5f378 3884f080 3863b948 4bbf6925 60000000 <0fe00000> 4bffff7c fba10088 4bbf6e41 ---[ end trace b925b67a74a1d8d1 ]--- BUG: Kernel NULL pointer dereference at 0x00000010 Faulting instruction address: 0xc00800000d44fc04 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV Modules linked in: kvm_hv kvm dm_mod vhost_net vhost tap xt_CHECKSUM iptable_mangle xt_MASQUERADE iptable_nat nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ipt_REJECT nf_reject_ipv4 tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter squashfs loop fuse i2c_dev sg ofpart ocxl powernv_flash at24 xts mtd uio_pdrv_genirq vmx_crypto opal_prd ipmi_powernv uio ipmi_devintf ipmi_msghandler ibmpowernv ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables ext4 mbcache jbd2 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq libcrc32c raid1 raid0 linear sd_mod ast i2c_algo_bit drm_vram_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm ahci libahci libata tg3 drm_panel_orientation_quirks [last unloaded: kvm] CPU: 24 PID: 88176 Comm: qemu-system-ppc Tainted: G W 5.3.0-xive-nr-servers-5.3-gku+ linux-kernel-labs#38 NIP: c00800000d44fc04 LR: c00800000d44fc00 CTR: c0000000001cd970 REGS: c000003f7f9938e0 TRAP: 0300 Tainted: G W (5.3.0-xive-nr-servers-5.3-gku+) MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 24228882 XER: 20040000 CFAR: c0000000001cd9ac DAR: 0000000000000010 DSISR: 40000000 IRQMASK: 0 GPR00: c00800000d44fc00 c000003f7f993b70 c00800000d468300 0000000000000000 GPR04: 00000000000000c7 0000000000000000 0000000000000000 c000003ffacd06d8 GPR08: 0000000000000000 c000003ffacd0738 0000000000000000 fffffffffffffffd GPR12: 0000000000000040 c000003ffffeb800 0000000000000000 000000012f4ce5a1 GPR16: 000000012ef5a0c8 0000000000000000 000000012f113bb0 0000000000000000 GPR20: 000000012f45d918 00007ffffe0d9a80 000000012f4f5df0 000000012ef8c9f8 GPR24: 0000000000000001 0000000000000000 c000003fe4501ed0 c000003f8b1d0000 GPR28: c0000033314689c0 c000003fe4501c00 c000003fe4501e70 c000003fe4501e90 NIP [c00800000d44fc04] kvmppc_xive_cleanup_vcpu+0xfc/0x210 [kvm] LR [c00800000d44fc00] kvmppc_xive_cleanup_vcpu+0xf8/0x210 [kvm] Call Trace: [c000003f7f993b70] [c00800000d44fc00] kvmppc_xive_cleanup_vcpu+0xf8/0x210 [kvm] (unreliable) [c000003f7f993bd0] [c00800000d450bd4] kvmppc_xive_release+0xdc/0x1b0 [kvm] [c000003f7f993c30] [c00800000d436a98] kvm_device_release+0xb0/0x110 [kvm] [c000003f7f993c70] [c00000000046730c] __fput+0xec/0x320 [c000003f7f993cd0] [c000000000164ae0] task_work_run+0x150/0x1c0 [c000003f7f993d30] [c000000000025034] do_notify_resume+0x304/0x440 [c000003f7f993e20] [c00000000000dcc4] ret_from_except_lite+0x70/0x74 Instruction dump: 3bff0008 7fbfd040 419e0054 847e0004 2fa30000 419effec e93d0000 8929203c 2f890000 419effb8 4800821d e8410018 <e9230010> e9490008 9b2a0039 7c0004ac ---[ end trace b925b67a74a1d8d2 ]--- Kernel panic - not syncing: Fatal exception This affects both XIVE and XICS-on-XIVE devices since the beginning. Check the VP id instead of the vCPU id when a new vCPU is connected. The allocation of the XIVE CPU structure in kvmppc_xive_connect_vcpu() is moved after the check to avoid the need for rollback. Cc: [email protected] # v4.12+ Signed-off-by: Greg Kurz <[email protected]> Reviewed-by: Cédric Le Goater <[email protected]> Signed-off-by: Paul Mackerras <[email protected]>

Daniel Vetter uncovered a nasty cycle in using the mmu-notifiers to invalidate userptr objects which also happen to be pulled into GGTT mmaps. That is when we unbind the userptr object (on mmu invalidation), we revoke all CPU mmaps, which may then recurse into mmu invalidation. We looked for ways of breaking the cycle, but the revocation on invalidation is required and cannot be avoided. The only solution we could see was to not allow such GGTT bindings of userptr objects in the first place. In practice, no one really wants to use a GGTT mmapping of a CPU pointer... Just before Daniel's explosive lockdep patches land in v5.4-rc1, we got a genuine blip from CI: <4>[ 246.793958] ====================================================== <4>[ 246.793972] WARNING: possible circular locking dependency detected <4>[ 246.793989] 5.3.0-gbd6c56f50d15-drmtip_372+ #1 Tainted: G U <4>[ 246.794003] ------------------------------------------------------ <4>[ 246.794017] kswapd0/145 is trying to acquire lock: <4>[ 246.794030] 000000003f565be6 (&dev->struct_mutex/1){+.+.}, at: userptr_mn_invalidate_range_start+0x18f/0x220 [i915] <4>[ 246.794250] but task is already holding lock: <4>[ 246.794263] 000000001799cef9 (&anon_vma->rwsem){++++}, at: page_lock_anon_vma_read+0xe6/0x2a0 <4>[ 246.794291] which lock already depends on the new lock. <4>[ 246.794307] the existing dependency chain (in reverse order) is: <4>[ 246.794322] -> #3 (&anon_vma->rwsem){++++}: <4>[ 246.794344] down_write+0x33/0x70 <4>[ 246.794357] __vma_adjust+0x3d9/0x7b0 <4>[ 246.794370] __split_vma+0x16a/0x180 <4>[ 246.794385] mprotect_fixup+0x2a5/0x320 <4>[ 246.794399] do_mprotect_pkey+0x208/0x2e0 <4>[ 246.794413] __x64_sys_mprotect+0x16/0x20 <4>[ 246.794429] do_syscall_64+0x55/0x1c0 <4>[ 246.794443] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4>[ 246.794456] -> #2 (&mapping->i_mmap_rwsem){++++}: <4>[ 246.794478] down_write+0x33/0x70 <4>[ 246.794493] unmap_mapping_pages+0x48/0x130 <4>[ 246.794519] i915_vma_revoke_mmap+0x81/0x1b0 [i915] <4>[ 246.794519] i915_vma_unbind+0x11d/0x4a0 [i915] <4>[ 246.794519] i915_vma_destroy+0x31/0x300 [i915] <4>[ 246.794519] __i915_gem_free_objects+0xb8/0x4b0 [i915] <4>[ 246.794519] drm_file_free.part.0+0x1e6/0x290 <4>[ 246.794519] drm_release+0xa6/0xe0 <4>[ 246.794519] __fput+0xc2/0x250 <4>[ 246.794519] task_work_run+0x82/0xb0 <4>[ 246.794519] do_exit+0x35b/0xdb0 <4>[ 246.794519] do_group_exit+0x34/0xb0 <4>[ 246.794519] __x64_sys_exit_group+0xf/0x10 <4>[ 246.794519] do_syscall_64+0x55/0x1c0 <4>[ 246.794519] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4>[ 246.794519] -> #1 (&vm->mutex){+.+.}: <4>[ 246.794519] i915_gem_shrinker_taints_mutex+0x6d/0xe0 [i915] <4>[ 246.794519] i915_address_space_init+0x9f/0x160 [i915] <4>[ 246.794519] i915_ggtt_init_hw+0x55/0x170 [i915] <4>[ 246.794519] i915_driver_probe+0xc9f/0x1620 [i915] <4>[ 246.794519] i915_pci_probe+0x43/0x1b0 [i915] <4>[ 246.794519] pci_device_probe+0x9e/0x120 <4>[ 246.794519] really_probe+0xea/0x3d0 <4>[ 246.794519] driver_probe_device+0x10b/0x120 <4>[ 246.794519] device_driver_attach+0x4a/0x50 <4>[ 246.794519] __driver_attach+0x97/0x130 <4>[ 246.794519] bus_for_each_dev+0x74/0xc0 <4>[ 246.794519] bus_add_driver+0x13f/0x210 <4>[ 246.794519] driver_register+0x56/0xe0 <4>[ 246.794519] do_one_initcall+0x58/0x300 <4>[ 246.794519] do_init_module+0x56/0x1f6 <4>[ 246.794519] load_module+0x25bd/0x2a40 <4>[ 246.794519] __se_sys_finit_module+0xd3/0xf0 <4>[ 246.794519] do_syscall_64+0x55/0x1c0 <4>[ 246.794519] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4>[ 246.794519] -> #0 (&dev->struct_mutex/1){+.+.}: <4>[ 246.794519] __lock_acquire+0x15d8/0x1e90 <4>[ 246.794519] lock_acquire+0xa6/0x1c0 <4>[ 246.794519] __mutex_lock+0x9d/0x9b0 <4>[ 246.794519] userptr_mn_invalidate_range_start+0x18f/0x220 [i915] <4>[ 246.794519] __mmu_notifier_invalidate_range_start+0x85/0x110 <4>[ 246.794519] try_to_unmap_one+0x76b/0x860 <4>[ 246.794519] rmap_walk_anon+0x104/0x280 <4>[ 246.794519] try_to_unmap+0xc0/0xf0 <4>[ 246.794519] shrink_page_list+0x561/0xc10 <4>[ 246.794519] shrink_inactive_list+0x220/0x440 <4>[ 246.794519] shrink_node_memcg+0x36e/0x740 <4>[ 246.794519] shrink_node+0xcb/0x490 <4>[ 246.794519] balance_pgdat+0x241/0x580 <4>[ 246.794519] kswapd+0x16c/0x530 <4>[ 246.794519] kthread+0x119/0x130 <4>[ 246.794519] ret_from_fork+0x24/0x50 <4>[ 246.794519] other info that might help us debug this: <4>[ 246.794519] Chain exists of: &dev->struct_mutex/1 --> &mapping->i_mmap_rwsem --> &anon_vma->rwsem <4>[ 246.794519] Possible unsafe locking scenario: <4>[ 246.794519] CPU0 CPU1 <4>[ 246.794519] ---- ---- <4>[ 246.794519] lock(&anon_vma->rwsem); <4>[ 246.794519] lock(&mapping->i_mmap_rwsem); <4>[ 246.794519] lock(&anon_vma->rwsem); <4>[ 246.794519] lock(&dev->struct_mutex/1); <4>[ 246.794519] *** DEADLOCK *** v2: Say no to mmap_ioctl Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111744 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111870 Signed-off-by: Chris Wilson <[email protected]> Cc: Tvrtko Ursulin <[email protected]> Cc: Daniel Vetter <[email protected]> Cc: [email protected] Reviewed-by: Tvrtko Ursulin <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] (cherry picked from commit a431174) Signed-off-by: Rodrigo Vivi <[email protected]>

Both multi_cpu_stop() and set_state() access multi_stop_data::state racily using plain accesses. These are subject to compiler transformations which could break the intended behaviour of the code, and this situation is detected by KCSAN on both arm64 and x86 (splats below). Improve matters by using READ_ONCE() and WRITE_ONCE() to ensure that the compiler cannot elide, replay, or tear loads and stores. In multi_cpu_stop() the two loads of multi_stop_data::state are expected to be a consistent value, so snapshot the value into a temporary variable to ensure this. The state transitions are serialized by atomic manipulation of multi_stop_data::num_threads, and other fields in multi_stop_data are not modified while subject to concurrent reads. KCSAN splat on arm64: | BUG: KCSAN: data-race in multi_cpu_stop+0xa8/0x198 and set_state+0x80/0xb0 | | write to 0xffff00001003bd00 of 4 bytes by task 24 on cpu 3: | set_state+0x80/0xb0 | multi_cpu_stop+0x16c/0x198 | cpu_stopper_thread+0x170/0x298 | smpboot_thread_fn+0x40c/0x560 | kthread+0x1a8/0x1b0 | ret_from_fork+0x10/0x18 | | read to 0xffff00001003bd00 of 4 bytes by task 14 on cpu 1: | multi_cpu_stop+0xa8/0x198 | cpu_stopper_thread+0x170/0x298 | smpboot_thread_fn+0x40c/0x560 | kthread+0x1a8/0x1b0 | ret_from_fork+0x10/0x18 | | Reported by Kernel Concurrency Sanitizer on: | CPU: 1 PID: 14 Comm: migration/1 Not tainted 5.3.0-00007-g67ab35a199f4-dirty #3 | Hardware name: linux,dummy-virt (DT) KCSAN splat on x86: | write to 0xffffb0bac0013e18 of 4 bytes by task 19 on cpu 2: | set_state kernel/stop_machine.c:170 [inline] | ack_state kernel/stop_machine.c:177 [inline] | multi_cpu_stop+0x1a4/0x220 kernel/stop_machine.c:227 | cpu_stopper_thread+0x19e/0x280 kernel/stop_machine.c:516 | smpboot_thread_fn+0x1a8/0x300 kernel/smpboot.c:165 | kthread+0x1b5/0x200 kernel/kthread.c:255 | ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:352 | | read to 0xffffb0bac0013e18 of 4 bytes by task 44 on cpu 7: | multi_cpu_stop+0xb4/0x220 kernel/stop_machine.c:213 | cpu_stopper_thread+0x19e/0x280 kernel/stop_machine.c:516 | smpboot_thread_fn+0x1a8/0x300 kernel/smpboot.c:165 | kthread+0x1b5/0x200 kernel/kthread.c:255 | ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:352 | | Reported by Kernel Concurrency Sanitizer on: | CPU: 7 PID: 44 Comm: migration/7 Not tainted 5.3.0+ #1 | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Signed-off-by: Mark Rutland <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Acked-by: Marco Elver <[email protected]> Link: https://lkml.kernel.org/r/[email protected]

We have a test case like block/001 in blktests, which will create a scsi device by loading scsi_debug module and then try to delete the device by sysfs interface. At the same time, it may remove the scsi_debug module. And getting a invalid paging request BUG_ON as following: [ 34.625854] BUG: unable to handle page fault for address: ffffffffa0016bb8 [ 34.629189] Oops: 0000 [#1] SMP PTI [ 34.629618] CPU: 1 PID: 450 Comm: bash Tainted: G W 5.4.0-rc3+ torvalds#473 [ 34.632524] RIP: 0010:scsi_proc_hostdir_rm+0x5/0xa0 [ 34.643555] CR2: ffffffffa0016bb8 CR3: 000000012cd88000 CR4: 00000000000006e0 [ 34.644545] Call Trace: [ 34.644907] scsi_host_dev_release+0x6b/0x1f0 [ 34.645511] device_release+0x74/0x110 [ 34.646046] kobject_put+0x116/0x390 [ 34.646559] put_device+0x17/0x30 [ 34.647041] scsi_target_dev_release+0x2b/0x40 [ 34.647652] device_release+0x74/0x110 [ 34.648186] kobject_put+0x116/0x390 [ 34.648691] put_device+0x17/0x30 [ 34.649157] scsi_device_dev_release_usercontext+0x2e8/0x360 [ 34.649953] execute_in_process_context+0x29/0x80 [ 34.650603] scsi_device_dev_release+0x20/0x30 [ 34.651221] device_release+0x74/0x110 [ 34.651732] kobject_put+0x116/0x390 [ 34.652230] sysfs_unbreak_active_protection+0x3f/0x50 [ 34.652935] sdev_store_delete.cold.4+0x71/0x8f [ 34.653579] dev_attr_store+0x1b/0x40 [ 34.654103] sysfs_kf_write+0x3d/0x60 [ 34.654603] kernfs_fop_write+0x174/0x250 [ 34.655165] __vfs_write+0x1f/0x60 [ 34.655639] vfs_write+0xc7/0x280 [ 34.656117] ksys_write+0x6d/0x140 [ 34.656591] __x64_sys_write+0x1e/0x30 [ 34.657114] do_syscall_64+0xb1/0x400 [ 34.657627] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 34.658335] RIP: 0033:0x7f156f337130 During deleting scsi target, the scsi_debug module have been removed. Then, sdebug_driver_template belonged to the module cannot be accessd, resulting in scsi_proc_hostdir_rm() BUG_ON. To fix the bug, we add scsi_device_get() in sdev_store_delete() to try to increase refcount of module, avoiding the module been removed. Cc: [email protected] Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Yufen Yu <[email protected]> Reviewed-by: Bart Van Assche <[email protected]> Signed-off-by: Martin K. Petersen <[email protected]>

There are three places where we access uninitialized memmaps, namely: - /proc/kpagecount - /proc/kpageflags - /proc/kpagecgroup We have initialized memmaps either when the section is online or when the page was initialized to the ZONE_DEVICE. Uninitialized memmaps contain garbage and in the worst case trigger kernel BUGs, especially with CONFIG_PAGE_POISONING. For example, not onlining a DIMM during boot and calling /proc/kpagecount with CONFIG_PAGE_POISONING: :/# cat /proc/kpagecount > tmp.test BUG: unable to handle page fault for address: fffffffffffffffe #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 114616067 P4D 114616067 PUD 114618067 PMD 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 PID: 469 Comm: cat Not tainted 5.4.0-rc1-next-20191004+ linux-kernel-labs#11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.4 RIP: 0010:kpagecount_read+0xce/0x1e0 Code: e8 09 83 e0 3f 48 0f a3 02 73 2d 4c 89 e7 48 c1 e7 06 48 03 3d ab 51 01 01 74 1d 48 8b 57 08 480 RSP: 0018:ffffa14e409b7e78 EFLAGS: 00010202 RAX: fffffffffffffffe RBX: 0000000000020000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 00007f76b5595000 RDI: fffff35645000000 RBP: 00007f76b5595000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000140000 R13: 0000000000020000 R14: 00007f76b5595000 R15: ffffa14e409b7f08 FS: 00007f76b577d580(0000) GS:ffff8f41bd400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffffe CR3: 0000000078960000 CR4: 00000000000006f0 Call Trace: proc_reg_read+0x3c/0x60 vfs_read+0xc5/0x180 ksys_read+0x68/0xe0 do_syscall_64+0x5c/0xa0 entry_SYSCALL_64_after_hwframe+0x49/0xbe For now, let's drop support for ZONE_DEVICE from the three pseudo files in order to fix this. To distinguish offline memory (with garbage memmap) from ZONE_DEVICE memory with properly initialized memmaps, we would have to check get_dev_pagemap() and pfn_zone_device_reserved() right now. The usage of both (especially, special casing devmem) is frowned upon and needs to be reworked. The fundamental issue we have is: if (pfn_to_online_page(pfn)) { /* memmap initialized */ } else if (pfn_valid(pfn)) { /* * ??? * a) offline memory. memmap garbage. * b) devmem: memmap initialized to ZONE_DEVICE. * c) devmem: reserved for driver. memmap garbage. * (d) devmem: memmap currently initializing - garbage) */ } We'll leave the pfn_zone_device_reserved() check in stable_page_flags() in place as that function is also used from memory failure. We now no longer dump information about pages that are not in use anymore - offline. Link: http://lkml.kernel.org/r/[email protected] Fixes: f1dd2cd ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e] Signed-off-by: David Hildenbrand <[email protected]> Reported-by: Qian Cai <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Dan Williams <[email protected]> Cc: Alexey Dobriyan <[email protected]> Cc: Stephen Rothwell <[email protected]> Cc: Toshiki Fukasawa <[email protected]> Cc: Pankaj gupta <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Anthony Yznaga <[email protected]> Cc: "Aneesh Kumar K.V" <[email protected]> Cc: <[email protected]> [4.13+] Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

…pagetypeinfo Uninitialized memmaps contain garbage and in the worst case trigger kernel BUGs, especially with CONFIG_PAGE_POISONING. They should not get touched. For example, when not onlining a memory block that is spanned by a zone and reading /proc/pagetypeinfo with CONFIG_DEBUG_VM_PGFLAGS and CONFIG_PAGE_POISONING, we can trigger a kernel BUG: :/# echo 1 > /sys/devices/system/memory/memory40/online :/# echo 1 > /sys/devices/system/memory/memory42/online :/# cat /proc/pagetypeinfo > test.file page:fffff2c585200000 is uninitialized and poisoned raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) There is not page extension available. ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:1107! invalid opcode: 0000 [#1] SMP NOPTI Please note that this change does not affect ZONE_DEVICE, because pagetypeinfo_showmixedcount_print() is called from mm/vmstat.c:pagetypeinfo_showmixedcount() only for populated zones, and ZONE_DEVICE is never populated (zone->present_pages always 0). [[email protected]: move check to outer loop, add comment, rephrase description] Link: http://lkml.kernel.org/r/[email protected] Fixes: f1dd2cd ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visible after d0dc12e Signed-off-by: Qian Cai <[email protected]> Signed-off-by: David Hildenbrand <[email protected]> Acked-by: Michal Hocko <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: "Peter Zijlstra (Intel)" <[email protected]> Cc: Miles Chen <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Qian Cai <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: <[email protected]> [4.13+] Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

…pointer release Karsten reported the following panic in __free_slab() happening on a s390x machine: Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 0000000000000483 Fault in home space mode while using kernel ASCE. AS:00000000017d4007 R3:000000007fbd0007 S:000000007fbff000 P:000000000000003d Oops: 0004 ilc:3 Ý#1¨ PREEMPT SMP Modules linked in: tcp_diag inet_diag xt_tcpudp ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrack ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_at nf_nat CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-05872-g6133e3e4bada-dirty linux-kernel-labs#14 Hardware name: IBM 2964 NC9 702 (z/VM 6.4.0) Krnl PSW : 0704d00180000000 00000000003cadb6 (__free_slab+0x686/0x6b0) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 RI:0 EA:3 Krnl GPRS: 00000000f3a32928 0000000000000000 000000007fbf5d00 000000000117c4b8 0000000000000000 000000009e3291c1 0000000000000000 0000000000000000 0000000000000003 0000000000000008 000000002b478b00 000003d080a97600 0000000000000003 0000000000000008 000000002b478b00 000003d080a97600 000000000117ba00 000003e000057db0 00000000003cabcc 000003e000057c78 Krnl Code: 00000000003cada6: e310a1400004 lg %r1,320(%r10) 00000000003cadac: c0e50046c286 brasl %r14,ca32b8 #00000000003cadb2: a7f4fe36 brc 15,3caa1e >00000000003cadb6: e32060800024 stg %r2,128(%r6) 00000000003cadbc: a7f4fd9e brc 15,3ca8f8 00000000003cadc0: c0e50046790c brasl %r14,c99fd8 00000000003cadc6: a7f4fe2c brc 15,3caa 00000000003cadc6: a7f4fe2c brc 15,3caa1e 00000000003cadca: ecb1ffff00d9 aghik %r11,%r1,-1 Call Trace: (<00000000003cabcc> __free_slab+0x49c/0x6b0) <00000000001f5886> rcu_core+0x5a6/0x7e0 <0000000000ca2dea> __do_softirq+0xf2/0x5c0 <0000000000152644> irq_exit+0x104/0x130 <000000000010d222> do_IRQ+0x9a/0xf0 <0000000000ca2344> ext_int_handler+0x130/0x134 <0000000000103648> enabled_wait+0x58/0x128 (<0000000000103634> enabled_wait+0x44/0x128) <0000000000103b00> arch_cpu_idle+0x40/0x58 <0000000000ca0544> default_idle_call+0x3c/0x68 <000000000018eaa4> do_idle+0xec/0x1c0 <000000000018ee0e> cpu_startup_entry+0x36/0x40 <000000000122df34> arch_call_rest_init+0x5c/0x88 <0000000000000000> 0x0 INFO: lockdep is turned off. Last Breaking-Event-Address: <00000000003ca8f4> __free_slab+0x1c4/0x6b0 Kernel panic - not syncing: Fatal exception in interrupt The kernel panics on an attempt to dereference the NULL memcg pointer. When shutdown_cache() is called from the kmem_cache_destroy() context, a memcg kmem_cache might have empty slab pages in a partial list, which are still charged to the memory cgroup. These pages are released by free_partial() at the beginning of shutdown_cache(): either directly or by scheduling a RCU-delayed work (if the kmem_cache has the SLAB_TYPESAFE_BY_RCU flag). The latter case is when the reported panic can happen: memcg_unlink_cache() is called immediately after shrinking partial lists, without waiting for scheduled RCU works. It sets the kmem_cache->memcg_params.memcg pointer to NULL, and the following attempt to dereference it by __free_slab() from the RCU work context causes the panic. To fix the issue, let's postpone the release of the memcg pointer to destroy_memcg_params(). It's called from a separate work context by slab_caches_to_rcu_destroy_workfn(), which contains a full RCU barrier. This guarantees that all scheduled page release RCU works will complete before the memcg pointer will be zeroed. Big thanks for Karsten for the perfect report containing all necessary information, his help with the analysis of the problem and testing of the fix. Link: http://lkml.kernel.org/r/[email protected] Fixes: fb2f2b0 ("mm: memcg/slab: reparent memcg kmem_caches on cgroup removal") Signed-off-by: Roman Gushchin <[email protected]> Reported-by: Karsten Graul <[email protected]> Tested-by: Karsten Graul <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Reviewed-by: Shakeel Butt <[email protected]> Cc: Karsten Graul <[email protected]> Cc: Vladimir Davydov <[email protected]> Cc: David Rientjes <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

mount.ocfs2 failed when reading ocfs2 filesystem superblock encounters an error. ocfs2_initialize_super() returns before allocating ocfs2_wq. ocfs2_dismount_volume() triggers the following panic. Oct 15 16:09:27 cnwarekv-205120 kernel: On-disk corruption discovered.Please run fsck.ocfs2 once the filesystem is unmounted. Oct 15 16:09:27 cnwarekv-205120 kernel: (mount.ocfs2,22804,44): ocfs2_read_locked_inode:537 ERROR: status = -30 Oct 15 16:09:27 cnwarekv-205120 kernel: (mount.ocfs2,22804,44): ocfs2_init_global_system_inodes:458 ERROR: status = -30 Oct 15 16:09:27 cnwarekv-205120 kernel: (mount.ocfs2,22804,44): ocfs2_init_global_system_inodes:491 ERROR: status = -30 Oct 15 16:09:27 cnwarekv-205120 kernel: (mount.ocfs2,22804,44): ocfs2_initialize_super:2313 ERROR: status = -30 Oct 15 16:09:27 cnwarekv-205120 kernel: (mount.ocfs2,22804,44): ocfs2_fill_super:1033 ERROR: status = -30 ------------[ cut here ]------------ Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 11753 Comm: mount.ocfs2 Tainted: G E 4.14.148-200.ckv.x86_64 #1 Hardware name: Sugon H320-G30/35N16-US, BIOS 0SSDX017 12/21/2018 task: ffff967af0520000 task.stack: ffffa5f05484000 RIP: 0010:mutex_lock+0x19/0x20 Call Trace: flush_workqueue+0x81/0x460 ocfs2_shutdown_local_alloc+0x47/0x440 [ocfs2] ocfs2_dismount_volume+0x84/0x400 [ocfs2] ocfs2_fill_super+0xa4/0x1270 [ocfs2] ? ocfs2_initialize_super.isa.211+0xf20/0xf20 [ocfs2] mount_bdev+0x17f/0x1c0 mount_fs+0x3a/0x160 Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Yi Li <[email protected]> Reviewed-by: Joseph Qi <[email protected]> Cc: Mark Fasheh <[email protected]> Cc: Joel Becker <[email protected]> Cc: Junxiao Bi <[email protected]> Cc: Changwei Ge <[email protected]> Cc: Gang He <[email protected]> Cc: Jun Piao <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>

A race condition exists while initialiazing perf_trace_buf from perf_trace_init() and perf_kprobe_init(). CPU0 CPU1 perf_trace_init() mutex_lock(&event_mutex) perf_trace_event_init() perf_trace_event_reg() total_ref_count == 0 buf = alloc_percpu() perf_trace_buf[i] = buf tp_event->class->reg() //fails perf_kprobe_init() goto fail perf_trace_event_init() perf_trace_event_reg() fail: total_ref_count == 0 total_ref_count == 0 buf = alloc_percpu() perf_trace_buf[i] = buf tp_event->class->reg() total_ref_count++ free_percpu(perf_trace_buf[i]) perf_trace_buf[i] = NULL Any subsequent call to perf_trace_event_reg() will observe total_ref_count > 0, causing the perf_trace_buf to be always NULL. This can result in perf_trace_buf getting accessed from perf_trace_buf_alloc() without being initialized. Acquiring event_mutex in perf_kprobe_init() before calling perf_trace_event_init() should fix this race. The race caused the following bug: Unable to handle kernel paging request at virtual address 0000003106f2003c Mem abort info: ESR = 0x96000045 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000045 CM = 0, WnR = 1 user pgtable: 4k pages, 39-bit VAs, pgdp = ffffffc034b9b000 [0000003106f2003c] pgd=0000000000000000, pud=0000000000000000 Internal error: Oops: 96000045 [#1] PREEMPT SMP Process syz-executor (pid: 18393, stack limit = 0xffffffc093190000) pstate: 80400005 (Nzcv daif +PAN -UAO) pc : __memset+0x20/0x1ac lr : memset+0x3c/0x50 sp : ffffffc09319fc50 __memset+0x20/0x1ac perf_trace_buf_alloc+0x140/0x1a0 perf_trace_sys_enter+0x158/0x310 syscall_trace_enter+0x348/0x7c0 el0_svc_common+0x11c/0x368 el0_svc_handler+0x12c/0x198 el0_svc+0x8/0xc Ramdumps showed the following: total_ref_count = 3 perf_trace_buf = ( 0x0 -> NULL, 0x0 -> NULL, 0x0 -> NULL, 0x0 -> NULL) Link: http://lkml.kernel.org/r/[email protected] Cc: [email protected] Fixes: e12f03d ("perf/core: Implement the 'perf_kprobe' PMU") Acked-by: Song Liu <[email protected]> Signed-off-by: Prateek Sood <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>

Scheduled policy update work may end up racing with the freeing of the policy and unregistering the driver. One possible race is as below, where the cpufreq_driver is unregistered, but the scheduled work gets executed at later stage when, cpufreq_driver is NULL (i.e. after freeing the policy and driver). Unable to handle kernel NULL pointer dereference at virtual address 0000001c pgd = (ptrval) [0000001c] *pgd=80000080204003, *pmd=00000000 Internal error: Oops: 206 [#1] SMP THUMB2 Modules linked in: CPU: 0 PID: 34 Comm: kworker/0:1 Not tainted 5.4.0-rc3-00006-g67f5a8081a4b linux-kernel-labs#86 Hardware name: ARM-Versatile Express Workqueue: events handle_update PC is at cpufreq_set_policy+0x58/0x228 LR is at dev_pm_qos_read_value+0x77/0xac Control: 70c5387d Table: 80203000 DAC: fffffffd Process kworker/0:1 (pid: 34, stack limit = 0x(ptrval)) (cpufreq_set_policy) from (refresh_frequency_limits.part.24+0x37/0x48) (refresh_frequency_limits.part.24) from (handle_update+0x2f/0x38) (handle_update) from (process_one_work+0x16d/0x3cc) (process_one_work) from (worker_thread+0xff/0x414) (worker_thread) from (kthread+0xff/0x100) (kthread) from (ret_from_fork+0x11/0x28) Fixes: 67d874c ("cpufreq: Register notifiers with the PM QoS framework") Signed-off-by: Sudeep Holla <[email protected]> [ rjw: Cancel the work before dropping the QoS requests ] Acked-by: Viresh Kumar <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]>

When doing an out of tree build with O=, the nsdeps script constructs the absolute pathname of the module source file so that it can insert MODULE_IMPORT_NS statements in the right place. However, ${srctree} contains an unescaped path to the source tree, which, when used in a sed substitution, makes sed complain: ++ sed 's/[^ ]* *//home/jeyu/jeyu-linux\/&/g' sed: -e expression #1, char 12: unknown option to `s' The sed substitution command 's' ends prematurely with the forward slashes in the pathname, and sed errors out when it encounters the 'h', which is an invalid sed substitution option. To avoid escaping forward slashes ${srctree}, we can use '|' as an alternative delimiter for sed instead to avoid this error. Reviewed-by: Masahiro Yamada <[email protected]> Reviewed-by: Matthias Maennich <[email protected]> Tested-by: Matthias Maennich <[email protected]> Signed-off-by: Jessica Yu <[email protected]>

When the client hits reconnect it iterates over the mid pending queue marking entries for retry and moving them to a temporary list to issue callbacks later without holding GlobalMid_Lock. In the same time there is no guarantee that mids can't be removed from the temporary list or even freed completely by another thread. It may cause a temporary list corruption: [ 430.454897] list_del corruption. prev->next should be ffff98d3a8f316c0, but was 2e885cb266355469 [ 430.464668] ------------[ cut here ]------------ [ 430.466569] kernel BUG at lib/list_debug.c:51! [ 430.468476] invalid opcode: 0000 [#1] SMP PTI [ 430.470286] CPU: 0 PID: 13267 Comm: cifsd Kdump: loaded Not tainted 5.4.0-rc3+ linux-kernel-labs#19 [ 430.473472] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 [ 430.475872] RIP: 0010:__list_del_entry_valid.cold+0x31/0x55 ... [ 430.510426] Call Trace: [ 430.511500] cifs_reconnect+0x25e/0x610 [cifs] [ 430.513350] cifs_readv_from_socket+0x220/0x250 [cifs] [ 430.515464] cifs_read_from_socket+0x4a/0x70 [cifs] [ 430.517452] ? try_to_wake_up+0x212/0x650 [ 430.519122] ? cifs_small_buf_get+0x16/0x30 [cifs] [ 430.521086] ? allocate_buffers+0x66/0x120 [cifs] [ 430.523019] cifs_demultiplex_thread+0xdc/0xc30 [cifs] [ 430.525116] kthread+0xfb/0x130 [ 430.526421] ? cifs_handle_standard+0x190/0x190 [cifs] [ 430.528514] ? kthread_park+0x90/0x90 [ 430.530019] ret_from_fork+0x35/0x40 Fix this by obtaining extra references for mids being retried and marking them as MID_DELETED which indicates that such a mid has been dequeued from the pending list. Also move mid cleanup logic from DeleteMidQEntry to _cifs_mid_q_entry_release which is called when the last reference to a particular mid is put. This allows to avoid any use-after-free of response buffers. The patch needs to be backported to stable kernels. A stable tag is not mentioned below because the patch doesn't apply cleanly to any actively maintained stable kernel. Reviewed-by: Ronnie Sahlberg <[email protected]> Reviewed-and-tested-by: David Wysochanski <[email protected]> Signed-off-by: Pavel Shilovsky <[email protected]> Signed-off-by: Steve French <[email protected]>

tavip pushed a commit that referenced this issue Mar 25, 2018

Merge pull request #1 from linux-kernel-labs/master

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razvand added labs Kernel practical labs enhancement labels Mar 28, 2018

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Add a lab introducing USB drivers #1

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dbaluta commented Jul 14, 2017