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tcp: RFC6298 compliant TCP RTO calculation #1

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In RFC 6298 Standard TCP Retransmission Timeout (RTO) calculation, the
calculated RTO is rounded up to the Minimum RTO (MinRTO), if it is less.
The Linux implementation, as a discrepancy to the Standard, basically
adds the defined MinRTO to the calculated RTO. When comparing both
approaches, the Linux calculation seems to perform worse for sender
limited TCP flows like Telnet, SSH or constant bit rate encoded
transmissions, especially for Round Trip Times (RTT) of 50 ms to 800 ms.

Compared to the Linux implementation, the RFC 6298 proposed calculaiton
is more aggressively adapting to current network characteristics.The
decreased overestimation especially benefits sender limited TCP flows
like telnet, ssh or constant bit rate encoded transmissions.

As result of the changed RTO calculation the tcp_sock struct u32 variable
mdev_max_us from tcp.h is no longer used.

More details can be read under the following link:
https://docs.google.com/document/d/1pKmPfnQb6fDK4qpiNVkN8cQyGE4wYDZukcuZfR-BnnM/edit?usp=sharing

Signed-off-by: Daniel Metz [email protected]

Linux RTO calculation is adjusted to be RFC6298 Standard compliant.
MinRTO is no longer added to the computed RTO, RTO damping and
overestimation are decreased.

In RFC 6298 Standard TCP Retransmission Timeout (RTO) calculation the
calculated RTO is rounded up to the Minimum RTO (MinRTO), if it is less.
The Linux implementation as a discrepancy to the Standard basically
adds the defined MinRTO to the calculated RTO. When comparing both
approaches, the Linux calculation seems to perform worse for sender
limited TCP flows like Telnet, SSH or constant bit rate encoded
transmissions, especially for Round Trip Times (RTT) of 50ms to 800ms.

Compared to the Linux implementation the RFC 6298 proposed RTO
calculation performs better and more precise in adapting to current
network characteristics. Extensive measurements for bulk data did not
show a negative impact of the adjusted calculation.

Performance Comparison for sender-limited-flows:
Rate: 10Mbit/s, Delay: 200ms, Delay Variation: 10ms, Time between each
scheduled segment: 1s, Amount Data Segments: 300, Mean of 8 runs

Mean Response Waiting Time [milliseconds]

old 205.8  208.3  217.0  220.3  227.8  249.9  271.0  308.9
new 204.3  206.5  207.1  210.5  217.3  224.2  237.8  258.3

    0.5    1      1.5    2      3      5      7      10
Packet Error Rate [percent]

Detailed Analysis:
https://docs.google.com/document/d/1pKmPfnQb6fDK4qpiNVkN8cQyGE4wYDZukcuZfR-BnnM/edit?usp=sharing

Signed-off-by: Daniel Metz <[email protected]>
@danielmgit danielmgit closed this Jun 10, 2016
hgn pushed a commit that referenced this pull request Jun 14, 2016
The list of devices is protected by the device_list_mutex and the device
replace code, in its finishing phase correctly takes that mutex before
removing the source device from that list. However the readahead code was
iterating that list without acquiring the respective mutex leading to
crashes later on due to invalid memory accesses:

[125671.831036] general protection fault: 0000 [#1] PREEMPT SMP
[125671.832129] Modules linked in: btrfs dm_flakey dm_mod crc32c_generic xor raid6_pq acpi_cpufreq tpm_tis tpm ppdev evdev parport_pc psmouse sg parport
processor ser
[125671.834973] CPU: 10 PID: 19603 Comm: kworker/u32:19 Tainted: G        W       4.6.0-rc7-btrfs-next-29+ #1
[125671.834973] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[125671.834973] Workqueue: btrfs-readahead btrfs_readahead_helper [btrfs]
[125671.834973] task: ffff8801ac520540 ti: ffff8801ac918000 task.ti: ffff8801ac918000
[125671.834973] RIP: 0010:[<ffffffff81270479>]  [<ffffffff81270479>] __radix_tree_lookup+0x6a/0x105
[125671.834973] RSP: 0018:ffff8801ac91bc28  EFLAGS: 00010206
[125671.834973] RAX: 0000000000000000 RBX: 6b6b6b6b6b6b6b6a RCX: 0000000000000000
[125671.834973] RDX: 0000000000000000 RSI: 00000000000c1bff RDI: ffff88002ebd62a8
[125671.834973] RBP: ffff8801ac91bc70 R08: 0000000000000001 R09: 0000000000000000
[125671.834973] R10: ffff8801ac91bc70 R11: 0000000000000000 R12: ffff88002ebd62a8
[125671.834973] R13: 0000000000000000 R14: 0000000000000000 R15: 00000000000c1bff
[125671.834973] FS:  0000000000000000(0000) GS:ffff88023fd40000(0000) knlGS:0000000000000000
[125671.834973] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[125671.834973] CR2: 000000000073cae4 CR3: 00000000b7723000 CR4: 00000000000006e0
[125671.834973] Stack:
[125671.834973]  0000000000000000 ffff8801422d5600 ffff8802286bbc00 0000000000000000
[125671.834973]  0000000000000001 ffff8802286bbc00 00000000000c1bff 0000000000000000
[125671.834973]  ffff88002e639eb8 ffff8801ac91bc80 ffffffff81270541 ffff8801ac91bcb0
[125671.834973] Call Trace:
[125671.834973]  [<ffffffff81270541>] radix_tree_lookup+0xd/0xf
[125671.834973]  [<ffffffffa04ae6a6>] reada_peer_zones_set_lock+0x3e/0x60 [btrfs]
[125671.834973]  [<ffffffffa04ae8b9>] reada_pick_zone+0x29/0x103 [btrfs]
[125671.834973]  [<ffffffffa04af42f>] reada_start_machine_worker+0x129/0x2d3 [btrfs]
[125671.834973]  [<ffffffffa04880be>] btrfs_scrubparity_helper+0x185/0x3aa [btrfs]
[125671.834973]  [<ffffffffa0488341>] btrfs_readahead_helper+0xe/0x10 [btrfs]
[125671.834973]  [<ffffffff81069691>] process_one_work+0x271/0x4e9
[125671.834973]  [<ffffffff81069dda>] worker_thread+0x1eb/0x2c9
[125671.834973]  [<ffffffff81069bef>] ? rescuer_thread+0x2b3/0x2b3
[125671.834973]  [<ffffffff8106f403>] kthread+0xd4/0xdc
[125671.834973]  [<ffffffff8149e242>] ret_from_fork+0x22/0x40
[125671.834973]  [<ffffffff8106f32f>] ? kthread_stop+0x286/0x286

So fix this by taking the device_list_mutex in the readahead code. We
can't use here the lighter approach of using a rcu_read_lock() and
rcu_read_unlock() pair together with a list_for_each_entry_rcu() call
because we end up doing calls to sleeping functions (kzalloc()) in the
respective code path.

Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
When it's finishing, the device replace code iterates all extent maps
representing block group and for each one that has a stripe that refers
to the source device, it replaces its device with the target device.
However when it replaces the source device with the target device it,
the target device still has an ID of 0ULL (BTRFS_DEV_REPLACE_DEVID),
only after its ID is changed to match the one from the source device.
This leads to races with the chunk removal code that can temporarly see
a device with an ID of 0ULL and then attempt to use that ID to remove
items from the device tree and fail, causing a transaction abort:

[ 9238.594364] BTRFS info (device sdf): dev_replace from /dev/sdf (devid 3) to /dev/sde finished
[ 9238.594377] ------------[ cut here ]------------
[ 9238.594402] WARNING: CPU: 14 PID: 21566 at fs/btrfs/volumes.c:2771 btrfs_remove_chunk+0x2e5/0x793 [btrfs]
[ 9238.594403] BTRFS: Transaction aborted (error 1)
[ 9238.594416] Modules linked in: btrfs crc32c_generic acpi_cpufreq xor tpm_tis tpm raid6_pq ppdev parport_pc processor psmouse parport i2c_piix4 evdev sg i2c_core se
rio_raw pcspkr button loop autofs4 ext4 crc16 jbd2 mbcache sr_mod cdrom sd_mod ata_generic virtio_scsi ata_piix virtio_pci libata virtio_ring virtio e1000 scsi_mod fl
oppy [last unloaded: btrfs]
[ 9238.594418] CPU: 14 PID: 21566 Comm: btrfs-cleaner Not tainted 4.6.0-rc7-btrfs-next-29+ #1
[ 9238.594419] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 9238.594421]  0000000000000000 ffff88017f1dbc60 ffffffff8126b42c ffff88017f1dbcb0
[ 9238.594422]  0000000000000000 ffff88017f1dbca0 ffffffff81052b14 00000ad37f1dbd18
[ 9238.594423]  0000000000000001 ffff88018068a558 ffff88005c4b9c00 ffff880233f60db0
[ 9238.594424] Call Trace:
[ 9238.594428]  [<ffffffff8126b42c>] dump_stack+0x67/0x90
[ 9238.594430]  [<ffffffff81052b14>] __warn+0xc2/0xdd
[ 9238.594432]  [<ffffffff81052b7a>] warn_slowpath_fmt+0x4b/0x53
[ 9238.594434]  [<ffffffff8116c311>] ? kmem_cache_free+0x128/0x188
[ 9238.594450]  [<ffffffffa04d43f5>] btrfs_remove_chunk+0x2e5/0x793 [btrfs]
[ 9238.594452]  [<ffffffff8108e456>] ? arch_local_irq_save+0x9/0xc
[ 9238.594464]  [<ffffffffa04a26fa>] btrfs_delete_unused_bgs+0x317/0x382 [btrfs]
[ 9238.594476]  [<ffffffffa04a961d>] cleaner_kthread+0x1ad/0x1c7 [btrfs]
[ 9238.594489]  [<ffffffffa04a9470>] ? btree_invalidatepage+0x8e/0x8e [btrfs]
[ 9238.594490]  [<ffffffff8106f403>] kthread+0xd4/0xdc
[ 9238.594494]  [<ffffffff8149e242>] ret_from_fork+0x22/0x40
[ 9238.594495]  [<ffffffff8106f32f>] ? kthread_stop+0x286/0x286
[ 9238.594496] ---[ end trace 183efbe50275f059 ]---

The sequence of steps leading to this is like the following:

              CPU 1                                           CPU 2

 btrfs_dev_replace_finishing()

   at this point
   dev_replace->tgtdev->devid ==
   BTRFS_DEV_REPLACE_DEVID (0ULL)

   ...

   btrfs_start_transaction()
   btrfs_commit_transaction()

                                                     btrfs_delete_unused_bgs()
                                                       btrfs_remove_chunk()

                                                         looks up for the extent map
                                                         corresponding to the chunk

                                                         lock_chunks() (chunk_mutex)
                                                         check_system_chunk()
                                                         unlock_chunks() (chunk_mutex)

   locks fs_info->chunk_mutex

   btrfs_dev_replace_update_device_in_mapping_tree()
     --> iterates fs_info->mapping_tree and
         replaces the device in every extent
         map's map->stripes[] with
         dev_replace->tgtdev, which still has
         an id of 0ULL (BTRFS_DEV_REPLACE_DEVID)

                                                         iterates over all stripes from
                                                         the extent map

                                                           --> calls btrfs_free_dev_extent()
                                                               passing it the target device
                                                               that still has an ID of 0ULL

                                                           --> btrfs_free_dev_extent() fails
                                                             --> aborts current transaction

   finishes setting up the target device,
   namely it sets tgtdev->devid to the value
   of srcdev->devid (which is necessarily > 0)

   frees the srcdev

   unlocks fs_info->chunk_mutex

So fix this by taking the device list mutex while processing the stripes
for the chunk's extent map. This is similar to the race between device
replace and block group creation that was fixed by commit 50460e3
("Btrfs: fix race when finishing dev replace leading to transaction abort").

Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
While we are finishing a device replace operation, we can make a discard
operation (fs mounted with -o discard) do an invalid memory access like
the one reported by the following trace:

[ 3206.384654] general protection fault: 0000 [#1] PREEMPT SMP
[ 3206.387520] Modules linked in: dm_mod btrfs crc32c_generic xor raid6_pq acpi_cpufreq tpm_tis psmouse tpm ppdev sg parport_pc evdev i2c_piix4 parport
processor serio_raw i2c_core pcspkr button loop autofs4 ext4 crc16 jbd2 mbcache sr_mod cdrom ata_generic sd_mod virtio_scsi ata_piix libata virtio_pci
virtio_ring scsi_mod e1000 virtio floppy [last unloaded: btrfs]
[ 3206.388595] CPU: 14 PID: 29194 Comm: fsstress Not tainted 4.6.0-rc7-btrfs-next-29+ #1
[ 3206.388595] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 3206.388595] task: ffff88017ace0100 ti: ffff880171b98000 task.ti: ffff880171b98000
[ 3206.388595] RIP: 0010:[<ffffffff8124d233>]  [<ffffffff8124d233>] blkdev_issue_discard+0x5c/0x2a7
[ 3206.388595] RSP: 0018:ffff880171b9bb80  EFLAGS: 00010246
[ 3206.388595] RAX: ffff880171b9bc28 RBX: 000000000090d000 RCX: 0000000000000000
[ 3206.388595] RDX: ffffffff82fa1b48 RSI: ffffffff8179f46c RDI: ffffffff82fa1b48
[ 3206.388595] RBP: ffff880171b9bcc0 R08: 0000000000000000 R09: 0000000000000001
[ 3206.388595] R10: ffff880171b9bce0 R11: 000000000090f000 R12: ffff880171b9bbe8
[ 3206.388595] R13: 0000000000000010 R14: 0000000000004868 R15: 6b6b6b6b6b6b6b6b
[ 3206.388595] FS:  00007f6182e4e700(0000) GS:ffff88023fdc0000(0000) knlGS:0000000000000000
[ 3206.388595] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3206.388595] CR2: 00007f617c2bbb18 CR3: 000000017ad9c000 CR4: 00000000000006e0
[ 3206.388595] Stack:
[ 3206.388595]  0000000000004878 0000000000000000 0000000002400040 0000000000000000
[ 3206.388595]  0000000000000000 ffff880171b9bbe8 ffff880171b9bbb0 ffff880171b9bbb0
[ 3206.388595]  ffff880171b9bbc0 ffff880171b9bbc0 ffff880171b9bbd0 ffff880171b9bbd0
[ 3206.388595] Call Trace:
[ 3206.388595]  [<ffffffffa042899e>] btrfs_issue_discard+0x12f/0x143 [btrfs]
[ 3206.388595]  [<ffffffffa042899e>] ? btrfs_issue_discard+0x12f/0x143 [btrfs]
[ 3206.388595]  [<ffffffffa042e862>] btrfs_discard_extent+0x87/0xde [btrfs]
[ 3206.388595]  [<ffffffffa04303b5>] btrfs_finish_extent_commit+0xb2/0x1df [btrfs]
[ 3206.388595]  [<ffffffff8149c246>] ? __mutex_unlock_slowpath+0x150/0x15b
[ 3206.388595]  [<ffffffffa04464c4>] btrfs_commit_transaction+0x7fc/0x980 [btrfs]
[ 3206.388595]  [<ffffffff8149c246>] ? __mutex_unlock_slowpath+0x150/0x15b
[ 3206.388595]  [<ffffffffa0459af6>] btrfs_sync_file+0x38f/0x428 [btrfs]
[ 3206.388595]  [<ffffffff811a8292>] vfs_fsync_range+0x8c/0x9e
[ 3206.388595]  [<ffffffff811a82c0>] vfs_fsync+0x1c/0x1e
[ 3206.388595]  [<ffffffff811a8417>] do_fsync+0x31/0x4a
[ 3206.388595]  [<ffffffff811a8637>] SyS_fsync+0x10/0x14
[ 3206.388595]  [<ffffffff8149e025>] entry_SYSCALL_64_fastpath+0x18/0xa8
[ 3206.388595]  [<ffffffff81100c6b>] ? time_hardirqs_off+0x9/0x14
[ 3206.388595]  [<ffffffff8108e87d>] ? trace_hardirqs_off_caller+0x1f/0xaa

This happens because when we call btrfs_map_block() from
btrfs_discard_extent() to get a btrfs_bio structure, the device replace
operation has not finished yet, but before we use the device of one of the
stripes from the returned btrfs_bio structure, the device object is freed.

This is illustrated by the following diagram.

            CPU 1                                                  CPU 2

 btrfs_dev_replace_start()

 (...)

 btrfs_dev_replace_finishing()

   btrfs_start_transaction()
   btrfs_commit_transaction()

   (...)

                                                            btrfs_sync_file()
                                                              btrfs_start_transaction()

                                                              (...)

                                                              btrfs_commit_transaction()
                                                                btrfs_finish_extent_commit()
                                                                  btrfs_discard_extent()
                                                                    btrfs_map_block()
                                                                      --> returns a struct btrfs_bio
                                                                          with a stripe that has a
                                                                          device field pointing to
                                                                          source device of the replace
                                                                          operation (the device that
                                                                          is being replaced)

   mutex_lock(&uuid_mutex)
   mutex_lock(&fs_info->fs_devices->device_list_mutex)
   mutex_lock(&fs_info->chunk_mutex)

   btrfs_dev_replace_update_device_in_mapping_tree()
     --> iterates the mapping tree and for each
         extent map that has a stripe pointing to
         the source device, it updates the stripe
         to point to the target device instead

   btrfs_rm_dev_replace_blocked()
     --> waits for fs_info->bio_counter to go down to 0

   btrfs_rm_dev_replace_remove_srcdev()
     --> removes source device from the list of devices

   mutex_unlock(&fs_info->chunk_mutex)
   mutex_unlock(&fs_info->fs_devices->device_list_mutex)
   mutex_unlock(&uuid_mutex)

   btrfs_rm_dev_replace_free_srcdev()
     --> frees the source device

                                                                    --> iterates over all stripes
                                                                        of the returned struct
                                                                        btrfs_bio
                                                                    --> for each stripe it
                                                                        dereferences its device
                                                                        pointer
                                                                        --> it ends up finding a
                                                                            pointer to the device
                                                                            used as the source
                                                                            device for the replace
                                                                            operation and that was
                                                                            already freed

So fix this by surrounding the call to btrfs_map_block(), and the code
that uses the returned struct btrfs_bio, with calls to
btrfs_bio_counter_inc_blocked() and btrfs_bio_counter_dec(), so that
the finishing phase of the device replace operation blocks until the
the bio counter decreases to zero before it frees the source device.
This is the same approach we do at btrfs_map_bio() for example.

Signed-off-by: Filipe Manana <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
Currently, the mesh paths associated with a nexthop station are cleaned
up in the following code path:

    __sta_info_destroy_part1
    synchronize_net()
    __sta_info_destroy_part2
     -> cleanup_single_sta
       -> mesh_sta_cleanup
         -> mesh_plink_deactivate
           -> mesh_path_flush_by_nexthop

However, there are a couple of problems here:

1) the paths aren't flushed at all if the MPM is running in userspace
   (e.g. when using wpa_supplicant or authsae)

2) there is no synchronize_rcu between removing the path and readers
   accessing the nexthop, which means the following race is possible:

CPU0                            CPU1
~~~~                            ~~~~
                                sta_info_destroy_part1()
                                synchronize_net()
rcu_read_lock()
mesh_nexthop_resolve()
  mpath = mesh_path_lookup()
                                [...] -> mesh_path_flush_by_nexthop()
  sta = rcu_dereference(
    mpath->next_hop)
                                kfree(sta)
  access sta <-- CRASH

Fix both of these by unconditionally flushing paths before destroying
the sta, and by adding a synchronize_net() after path flush to ensure
no active readers can still dereference the sta.

Fixes this crash:

[  348.529295] BUG: unable to handle kernel paging request at 00020040
[  348.530014] IP: [<f929245d>] ieee80211_mps_set_frame_flags+0x40/0xaa [mac80211]
[  348.530014] *pde = 00000000
[  348.530014] Oops: 0000 [#1] PREEMPT
[  348.530014] Modules linked in: drbg ansi_cprng ctr ccm ppp_generic slhc ipt_MASQUERADE nf_nat_masquerade_ipv4 8021q ]
[  348.530014] CPU: 0 PID: 20597 Comm: wget Tainted: G           O 4.6.0-rc5-wt=V1 #1
[  348.530014] Hardware name: To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080016  11/07/2014
[  348.530014] task: f64fa280 ti: f4f9c000 task.ti: f4f9c000
[  348.530014] EIP: 0060:[<f929245d>] EFLAGS: 00010246 CPU: 0
[  348.530014] EIP is at ieee80211_mps_set_frame_flags+0x40/0xaa [mac80211]
[  348.530014] EAX: f4ce63e0 EBX: 00000088 ECX: f3788416 EDX: 00020008
[  348.530014] ESI: 00000000 EDI: 00000088 EBP: f6409a4c ESP: f6409a40
[  348.530014]  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
[  348.530014] CR0: 80050033 CR2: 00020040 CR3: 33190000 CR4: 00000690
[  348.530014] Stack:
[  348.530014]  00000000 f4ce63e0 f5f9bd80 f6409a64 f9291d80 0000ce67 f5d51e00 f4ce63e0
[  348.530014]  f3788416 f6409a80 f9291dc1 f4ce8320 f4ce63e0 f5d51e00 f4ce63e0 f4ce8320
[  348.530014]  f6409a98 f9277f6f 00000000 00000000 0000007c 00000000 f6409b2c f9278dd1
[  348.530014] Call Trace:
[  348.530014]  [<f9291d80>] mesh_nexthop_lookup+0xbb/0xc8 [mac80211]
[  348.530014]  [<f9291dc1>] mesh_nexthop_resolve+0x34/0xd8 [mac80211]
[  348.530014]  [<f9277f6f>] ieee80211_xmit+0x92/0xc1 [mac80211]
[  348.530014]  [<f9278dd1>] __ieee80211_subif_start_xmit+0x807/0x83c [mac80211]
[  348.530014]  [<c04df012>] ? sch_direct_xmit+0xd7/0x1b3
[  348.530014]  [<c022a8c6>] ? __local_bh_enable_ip+0x5d/0x7b
[  348.530014]  [<f956870c>] ? nf_nat_ipv4_out+0x4c/0xd0 [nf_nat_ipv4]
[  348.530014]  [<f957e036>] ? iptable_nat_ipv4_fn+0xf/0xf [iptable_nat]
[  348.530014]  [<c04c6f45>] ? netif_skb_features+0x14d/0x30a
[  348.530014]  [<f9278e10>] ieee80211_subif_start_xmit+0xa/0xe [mac80211]
[  348.530014]  [<c04c769c>] dev_hard_start_xmit+0x1f8/0x267
[  348.530014]  [<c04c7261>] ?  validate_xmit_skb.isra.120.part.121+0x10/0x253
[  348.530014]  [<c04defc6>] sch_direct_xmit+0x8b/0x1b3
[  348.530014]  [<c04c7a9c>] __dev_queue_xmit+0x2c8/0x513
[  348.530014]  [<c04c7cfb>] dev_queue_xmit+0xa/0xc
[  348.530014]  [<f91bfc7a>] batadv_send_skb_packet+0xd6/0xec [batman_adv]
[  348.530014]  [<f91bfdc4>] batadv_send_unicast_skb+0x15/0x4a [batman_adv]
[  348.530014]  [<f91b5938>] batadv_dat_send_data+0x27e/0x310 [batman_adv]
[  348.530014]  [<f91c30b5>] ? batadv_tt_global_hash_find.isra.11+0x8/0xa [batman_adv]
[  348.530014]  [<f91b63f3>] batadv_dat_snoop_outgoing_arp_request+0x208/0x23d [batman_adv]
[  348.530014]  [<f91c0cd9>] batadv_interface_tx+0x206/0x385 [batman_adv]
[  348.530014]  [<c04c769c>] dev_hard_start_xmit+0x1f8/0x267
[  348.530014]  [<c04c7261>] ?  validate_xmit_skb.isra.120.part.121+0x10/0x253
[  348.530014]  [<c04defc6>] sch_direct_xmit+0x8b/0x1b3
[  348.530014]  [<c04c7a9c>] __dev_queue_xmit+0x2c8/0x513
[  348.530014]  [<f80cbd2a>] ? igb_xmit_frame+0x57/0x72 [igb]
[  348.530014]  [<c04c7cfb>] dev_queue_xmit+0xa/0xc
[  348.530014]  [<f843a326>] br_dev_queue_push_xmit+0xeb/0xfb [bridge]
[  348.530014]  [<f843a35f>] br_forward_finish+0x29/0x74 [bridge]
[  348.530014]  [<f843a23b>] ? deliver_clone+0x3b/0x3b [bridge]
[  348.530014]  [<f843a714>] __br_forward+0x89/0xe7 [bridge]
[  348.530014]  [<f843a336>] ? br_dev_queue_push_xmit+0xfb/0xfb [bridge]
[  348.530014]  [<f843a234>] deliver_clone+0x34/0x3b [bridge]
[  348.530014]  [<f843a68b>] ? br_flood+0x95/0x95 [bridge]
[  348.530014]  [<f843a66d>] br_flood+0x77/0x95 [bridge]
[  348.530014]  [<f843a809>] br_flood_forward+0x13/0x1a [bridge]
[  348.530014]  [<f843a68b>] ? br_flood+0x95/0x95 [bridge]
[  348.530014]  [<f843b877>] br_handle_frame_finish+0x392/0x3db [bridge]
[  348.530014]  [<c04e9b2b>] ? nf_iterate+0x2b/0x6b
[  348.530014]  [<f843baa6>] br_handle_frame+0x1e6/0x240 [bridge]
[  348.530014]  [<f843b4e5>] ? br_handle_local_finish+0x6a/0x6a [bridge]
[  348.530014]  [<c04c4ba0>] __netif_receive_skb_core+0x43a/0x66b
[  348.530014]  [<f843b8c0>] ? br_handle_frame_finish+0x3db/0x3db [bridge]
[  348.530014]  [<c023cea4>] ? resched_curr+0x19/0x37
[  348.530014]  [<c0240707>] ? check_preempt_wakeup+0xbf/0xfe
[  348.530014]  [<c0255dec>] ? ktime_get_with_offset+0x5c/0xfc
[  348.530014]  [<c04c4fc1>] __netif_receive_skb+0x47/0x55
[  348.530014]  [<c04c57ba>] netif_receive_skb_internal+0x40/0x5a
[  348.530014]  [<c04c61ef>] napi_gro_receive+0x3a/0x94
[  348.530014]  [<f80ce8d5>] igb_poll+0x6fd/0x9ad [igb]
[  348.530014]  [<c0242bd8>] ? swake_up_locked+0x14/0x26
[  348.530014]  [<c04c5d29>] net_rx_action+0xde/0x250
[  348.530014]  [<c022a743>] __do_softirq+0x8a/0x163
[  348.530014]  [<c022a6b9>] ? __hrtimer_tasklet_trampoline+0x19/0x19
[  348.530014]  [<c021100f>] do_softirq_own_stack+0x26/0x2c
[  348.530014]  <IRQ>
[  348.530014]  [<c022a957>] irq_exit+0x31/0x6f
[  348.530014]  [<c0210eb2>] do_IRQ+0x8d/0xa0
[  348.530014]  [<c058152c>] common_interrupt+0x2c/0x40
[  348.530014] Code: e7 8c 00 66 81 ff 88 00 75 12 85 d2 75 0e b2 c3 b8 83 e9 29 f9 e8 a7 5f f9 c6 eb 74 66 81 e3 8c 005
[  348.530014] EIP: [<f929245d>] ieee80211_mps_set_frame_flags+0x40/0xaa [mac80211] SS:ESP 0068:f6409a40
[  348.530014] CR2: 0000000000020040
[  348.530014] ---[ end trace 48556ac26779732e ]---
[  348.530014] Kernel panic - not syncing: Fatal exception in interrupt
[  348.530014] Kernel Offset: disabled

Cc: [email protected]
Reported-by: Fred Veldini <[email protected]>
Tested-by: Fred Veldini <[email protected]>
Signed-off-by: Bob Copeland <[email protected]>
Signed-off-by: Johannes Berg <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
Found by syzkaller:

    WARNING: CPU: 3 PID: 15175 at arch/x86/kvm/x86.c:7705 __x86_set_memory_region+0x1dc/0x1f0 [kvm]()
    CPU: 3 PID: 15175 Comm: a.out Tainted: G        W       4.4.6-300.fc23.x86_64 #1
    Hardware name: LENOVO 2325F51/2325F51, BIOS G2ET32WW (1.12 ) 05/30/2012
     0000000000000286 00000000950899a7 ffff88011ab3fbf0 ffffffff813b542e
     0000000000000000 ffffffffa0966496 ffff88011ab3fc28 ffffffff810a40f2
     00000000000001fd 0000000000003000 ffff88014fc50000 0000000000000000
    Call Trace:
     [<ffffffff813b542e>] dump_stack+0x63/0x85
     [<ffffffff810a40f2>] warn_slowpath_common+0x82/0xc0
     [<ffffffff810a423a>] warn_slowpath_null+0x1a/0x20
     [<ffffffffa09251cc>] __x86_set_memory_region+0x1dc/0x1f0 [kvm]
     [<ffffffffa092521b>] x86_set_memory_region+0x3b/0x60 [kvm]
     [<ffffffffa09bb61c>] vmx_set_tss_addr+0x3c/0x150 [kvm_intel]
     [<ffffffffa092f4d4>] kvm_arch_vm_ioctl+0x654/0xbc0 [kvm]
     [<ffffffffa091d31a>] kvm_vm_ioctl+0x9a/0x6f0 [kvm]
     [<ffffffff81241248>] do_vfs_ioctl+0x298/0x480
     [<ffffffff812414a9>] SyS_ioctl+0x79/0x90
     [<ffffffff817a04ee>] entry_SYSCALL_64_fastpath+0x12/0x71

Testcase:

    #include <unistd.h>
    #include <sys/ioctl.h>
    #include <fcntl.h>
    #include <string.h>
    #include <linux/kvm.h>

    long r[8];

    int main()
    {
        memset(r, -1, sizeof(r));
	r[2] = open("/dev/kvm", O_RDONLY|O_TRUNC);
        r[3] = ioctl(r[2], KVM_CREATE_VM, 0x0ul);
        r[5] = ioctl(r[3], KVM_SET_TSS_ADDR, 0x20000000ul);
        r[7] = ioctl(r[3], KVM_SET_TSS_ADDR, 0x20000000ul);
        return 0;
    }

Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Radim Krčmář <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
This cannot be returned by KVM_GET_VCPU_EVENTS, so it is okay to return
EINVAL.  It causes a WARN from exception_type:

    WARNING: CPU: 3 PID: 16732 at arch/x86/kvm/x86.c:345 exception_type+0x49/0x50 [kvm]()
    CPU: 3 PID: 16732 Comm: a.out Tainted: G        W       4.4.6-300.fc23.x86_64 #1
    Hardware name: LENOVO 2325F51/2325F51, BIOS G2ET32WW (1.12 ) 05/30/2012
     0000000000000286 000000006308a48b ffff8800bec7fcf8 ffffffff813b542e
     0000000000000000 ffffffffa0966496 ffff8800bec7fd30 ffffffff810a40f2
     ffff8800552a8000 0000000000000000 00000000002c267c 0000000000000001
    Call Trace:
     [<ffffffff813b542e>] dump_stack+0x63/0x85
     [<ffffffff810a40f2>] warn_slowpath_common+0x82/0xc0
     [<ffffffff810a423a>] warn_slowpath_null+0x1a/0x20
     [<ffffffffa0924809>] exception_type+0x49/0x50 [kvm]
     [<ffffffffa0934622>] kvm_arch_vcpu_ioctl_run+0x10a2/0x14e0 [kvm]
     [<ffffffffa091c04d>] kvm_vcpu_ioctl+0x33d/0x620 [kvm]
     [<ffffffff81241248>] do_vfs_ioctl+0x298/0x480
     [<ffffffff812414a9>] SyS_ioctl+0x79/0x90
     [<ffffffff817a04ee>] entry_SYSCALL_64_fastpath+0x12/0x71
    ---[ end trace b1a0391266848f50 ]---

Testcase (beautified/reduced from syzkaller output):

    #include <unistd.h>
    #include <sys/syscall.h>
    #include <string.h>
    #include <stdint.h>
    #include <fcntl.h>
    #include <sys/ioctl.h>
    #include <linux/kvm.h>

    long r[31];

    int main()
    {
        memset(r, -1, sizeof(r));
        r[2] = open("/dev/kvm", O_RDONLY);
        r[3] = ioctl(r[2], KVM_CREATE_VM, 0);
        r[7] = ioctl(r[3], KVM_CREATE_VCPU, 0);

        struct kvm_vcpu_events ve = {
                .exception.injected = 1,
                .exception.nr = 0xd4
        };
        r[27] = ioctl(r[7], KVM_SET_VCPU_EVENTS, &ve);
        r[30] = ioctl(r[7], KVM_RUN, 0);
        return 0;
    }

Reported-by: Dmitry Vyukov <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Radim Krčmář <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
Found by syzkaller:

    BUG: unable to handle kernel NULL pointer dereference at 0000000000000120
    IP: [<ffffffffa0797202>] kvm_irq_map_gsi+0x12/0x90 [kvm]
    PGD 6f80b067 PUD b6535067 PMD 0
    Oops: 0000 [#1] SMP
    CPU: 3 PID: 4988 Comm: a.out Not tainted 4.4.9-300.fc23.x86_64 #1
    [...]
    Call Trace:
     [<ffffffffa0795f62>] irqfd_update+0x32/0xc0 [kvm]
     [<ffffffffa0796c7c>] kvm_irqfd+0x3dc/0x5b0 [kvm]
     [<ffffffffa07943f4>] kvm_vm_ioctl+0x164/0x6f0 [kvm]
     [<ffffffff81241648>] do_vfs_ioctl+0x298/0x480
     [<ffffffff812418a9>] SyS_ioctl+0x79/0x90
     [<ffffffff817a1062>] tracesys_phase2+0x84/0x89
    Code: b5 71 a7 e0 5b 41 5c 41 5d 5d f3 c3 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 8b 8f 10 2e 00 00 31 c0 48 89 e5 <39> 91 20 01 00 00 76 6a 48 63 d2 48 8b 94 d1 28 01 00 00 48 85
    RIP  [<ffffffffa0797202>] kvm_irq_map_gsi+0x12/0x90 [kvm]
     RSP <ffff8800926cbca8>
    CR2: 0000000000000120

Testcase:

    #include <unistd.h>
    #include <sys/syscall.h>
    #include <string.h>
    #include <stdint.h>
    #include <linux/kvm.h>
    #include <fcntl.h>
    #include <sys/ioctl.h>

    long r[26];

    int main()
    {
        memset(r, -1, sizeof(r));
        r[2] = open("/dev/kvm", 0);
        r[3] = ioctl(r[2], KVM_CREATE_VM, 0);

        struct kvm_irqfd ifd;
        ifd.fd = syscall(SYS_eventfd2, 5, 0);
        ifd.gsi = 3;
        ifd.flags = 2;
        ifd.resamplefd = ifd.fd;
        r[25] = ioctl(r[3], KVM_IRQFD, &ifd);
        return 0;
    }

Reported-by: Dmitry Vyukov <[email protected]>
Cc: [email protected]
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Radim Krčmář <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
MOV to DR6 or DR7 causes a #GP if an attempt is made to write a 1 to
any of bits 63:32.  However, this is not detected at KVM_SET_DEBUGREGS
time, and the next KVM_RUN oopses:

   general protection fault: 0000 [#1] SMP
   CPU: 2 PID: 14987 Comm: a.out Not tainted 4.4.9-300.fc23.x86_64 #1
   Hardware name: LENOVO 2325F51/2325F51, BIOS G2ET32WW (1.12 ) 05/30/2012
   [...]
   Call Trace:
    [<ffffffffa072c93d>] kvm_arch_vcpu_ioctl_run+0x141d/0x14e0 [kvm]
    [<ffffffffa071405d>] kvm_vcpu_ioctl+0x33d/0x620 [kvm]
    [<ffffffff81241648>] do_vfs_ioctl+0x298/0x480
    [<ffffffff812418a9>] SyS_ioctl+0x79/0x90
    [<ffffffff817a0f2e>] entry_SYSCALL_64_fastpath+0x12/0x71
   Code: 55 83 ff 07 48 89 e5 77 27 89 ff ff 24 fd 90 87 80 81 0f 23 fe 5d c3 0f 23 c6 5d c3 0f 23 ce 5d c3 0f 23 d6 5d c3 0f 23 de 5d c3 <0f> 23 f6 5d c3 0f 0b 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00
   RIP  [<ffffffff810639eb>] native_set_debugreg+0x2b/0x40
    RSP <ffff88005836bd50>

Testcase (beautified/reduced from syzkaller output):

    #include <unistd.h>
    #include <sys/syscall.h>
    #include <string.h>
    #include <stdint.h>
    #include <linux/kvm.h>
    #include <fcntl.h>
    #include <sys/ioctl.h>

    long r[8];

    int main()
    {
        struct kvm_debugregs dr = { 0 };

        r[2] = open("/dev/kvm", O_RDONLY);
        r[3] = ioctl(r[2], KVM_CREATE_VM, 0);
        r[4] = ioctl(r[3], KVM_CREATE_VCPU, 7);

        memcpy(&dr,
               "\x5d\x6a\x6b\xe8\x57\x3b\x4b\x7e\xcf\x0d\xa1\x72"
               "\xa3\x4a\x29\x0c\xfc\x6d\x44\x00\xa7\x52\xc7\xd8"
               "\x00\xdb\x89\x9d\x78\xb5\x54\x6b\x6b\x13\x1c\xe9"
               "\x5e\xd3\x0e\x40\x6f\xb4\x66\xf7\x5b\xe3\x36\xcb",
               48);
        r[7] = ioctl(r[4], KVM_SET_DEBUGREGS, &dr);
        r[6] = ioctl(r[4], KVM_RUN, 0);
    }

Reported-by: Dmitry Vyukov <[email protected]>
Cc: [email protected]
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Radim Krčmář <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
A regression was introduced in commit 9c34989 ("brcmfmac: revise
handling events in receive path") which moves eth_type_trans() call
to brcmf_rx_frame(). Msgbuf layer doesn't use brcmf_rx_frame() but invokes
brcmf_netif_rx() directly. In such case the Ethernet header was not
stripped out resulting in null pointer dereference in the networking
stack.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000048
IP: [<ffffffff814c3ce6>] enqueue_to_backlog+0x56/0x260
PGD 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: fuse ipt_MASQUERADE nf_nat_masquerade_ipv4
iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 xt_addrtype
[...]
rtsx_pci scsi_mod usbcore usb_common i8042 serio nvme nvme_core
CPU: 7 PID: 1340 Comm: irq/136-brcmf_p Not tainted 4.7.0-rc1-mainline #1
Hardware name: Dell Inc. XPS 15 9550/0N7TVV, BIOS 01.02.00 04/07/2016
task: ffff8804a0c5bd00 ti: ffff88049e124000 task.ti: ffff88049e124000
RIP: 0010:[<ffffffff814c3ce6>] [<ffffffff814c3ce6>]
enqueue_to_backlog+0x56/0x260
RSP: 0018:ffff88049e127ca0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8804bddd7c40 RCX: 000000000000002f
RDX: 0000000000000000 RSI: 0000000000000007 RDI: ffff8804bddd7d4c
RBP: ffff88049e127ce8 R08: 0000000000000000 R09: 0000000000000000
R10: ffff8804bddd12c0 R11: 000000000000149e R12: 0000000000017c40
R13: ffff88049e127d08 R14: ffff8804a9bd6d00 R15: ffff8804bddd7d4c
FS: 0000000000000000(0000) GS:ffff8804bddc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000048 CR3: 0000000001806000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
ffff8804bdddad00 ffff8804ad089e00 0000000000000000 0000000000000282
0000000000000000 ffff8804a9bd6d00 ffff8804a1b27e00 ffff8804a9bd6d00
ffff88002ee88000 ffff88049e127d28 ffffffff814c3f3b ffffffff81311fc3
Call Trace:
[<ffffffff814c3f3b>] netif_rx_internal+0x4b/0x170
[<ffffffff81311fc3>] ? swiotlb_tbl_unmap_single+0xf3/0x120
[<ffffffff814c5467>] netif_rx_ni+0x27/0xc0
[<ffffffffa08519e9>] brcmf_netif_rx+0x49/0x70 [brcmfmac]
[<ffffffffa08564d4>] brcmf_msgbuf_process_rx+0x2b4/0x570 [brcmfmac]
[<ffffffff81020017>] ? __xen_set_pgd_hyper+0x57/0xd0
[<ffffffff810d60b0>] ? irq_forced_thread_fn+0x70/0x70
[<ffffffffa0857381>] brcmf_proto_msgbuf_rx_trigger+0x31/0xe0 [brcmfmac]
[<ffffffffa0861e8f>] brcmf_pcie_isr_thread+0x7f/0x110 [brcmfmac]
[<ffffffff810d60d0>] irq_thread_fn+0x20/0x50
[<ffffffff810d63ad>] irq_thread+0x12d/0x1c0
[<ffffffff815d07d5>] ? __schedule+0x2f5/0x7a0
[<ffffffff810d61d0>] ? wake_threads_waitq+0x30/0x30
[<ffffffff810d6280>] ? irq_thread_dtor+0xb0/0xb0
[<ffffffff81098ea8>] kthread+0xd8/0xf0
[<ffffffff815d4b7f>] ret_from_fork+0x1f/0x40
[<ffffffff81098dd0>] ? kthread_worker_fn+0x170/0x170
Code: 1c f5 60 9a 8e 81 9c 58 0f 1f 44 00 00 48 89 45 d0 fa 66 0f 1f
44 00 00 4c 8d bb 0c 01 00 00 4c 89 ff e8 5e 08 11 00 49 8b 56 20 <48>
8b 52 48 83 e2 01 74 10 8b 8b 08 01 00 00 8b 15 59 c5 42 00
RIP [<ffffffff814c3ce6>] enqueue_to_backlog+0x56/0x260
RSP <ffff88049e127ca0>
CR2: 0000000000000048

Fixes: 9c34989 ("brcmfmac: revise handling events in receive path")
Reported-by: Rafal Milecki <[email protected]>
Reported-by: Grey Christoforo <[email protected]>
Reviewed-by: Pieter-Paul Giesberts <[email protected]>
Reviewed-by: Arend Van Spriel <[email protected]>
Reviewed-by: Hante Meuleman <[email protected]>
Signed-off-by: Franky Lin <[email protected]>
[[email protected]: rephrased the commit message]
Signed-off-by: Arend van Spriel <[email protected]>
Signed-off-by: Kalle Valo <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
After the workqueue cleanup, we're registering workqueues based on
the presence of an ->edac_check function. When that is the case,
we're setting OP_RUNNING_POLL. But we forgot to check that in
edac_mc_reset_delay_period(), leading to:

  BUG: unable to handle kernel paging request at 0000000000015d10
  IP: [ .. ] queued_spin_lock_slowpath
  PGD 3ffcc8067 PUD 3ffc56067 PMD 0
  Oops: 0002 [#1] SMP
  Modules linked in: ...
  CPU: 1 PID: 2792 Comm: edactest Not tainted 4.6.0-dirty #1
  Hardware name: HP ProLiant MicroServer, BIOS O41     10/01/2013
  Stack:
  Call Trace:
    ? _raw_spin_lock_irqsave
    ? lock_timer_base.isra.34
    ? del_timer
    ? try_to_grab_pending
    ? mod_delayed_work_on
    ? edac_mc_reset_delay_period
    ? edac_set_poll_msec
    ? param_attr_store
    ? module_attr_store
    ? kernfs_fop_write
    ? __vfs_write
    ? __vfs_read
    ? __alloc_fd
    ? vfs_write
    ? SyS_write
    ? entry_SYSCALL_64_fastpath
  Code:
  RIP  [ .. ] queued_spin_lock_slowpath
   RSP <>
  CR2: 0000000000015d10
  ---[ end trace 3f286bc71cca15d1 ]---
  Kernel panic - not syncing: Fatal exception

Fix it.

Signed-off-by: Nicholas Krause <[email protected]>
Cc: <[email protected]> # 4.5
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: linux-edac <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ Rewrite commit message. ]
Signed-off-by: Borislav Petkov <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
With ARM64_64K_PAGES and RANDOMIZE_TEXT_OFFSET enabled, we hit the
following issue on the boot:

kernel BUG at arch/arm64/mm/mmu.c:480!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 4.6.0 torvalds#310
Hardware name: ARM Juno development board (r2) (DT)
task: ffff000008d58a80 ti: ffff000008d30000 task.ti: ffff000008d30000
PC is at map_kernel_segment+0x44/0xb0
LR is at paging_init+0x84/0x5b0
pc : [<ffff000008c450b4>] lr : [<ffff000008c451a4>] pstate: 600002c5

Call trace:
[<ffff000008c450b4>] map_kernel_segment+0x44/0xb0
[<ffff000008c451a4>] paging_init+0x84/0x5b0
[<ffff000008c42728>] setup_arch+0x198/0x534
[<ffff000008c40848>] start_kernel+0x70/0x388
[<ffff000008c401bc>] __primary_switched+0x30/0x74

Commit 7eb90f2 ("arm64: cover the .head.text section in the .text
segment mapping") removed the alignment between the .head.text and .text
sections, and used the _text rather than the _stext interval for mapping
the .text segment.

Prior to this commit _stext was always section aligned and didn't cause
any issue even when RANDOMIZE_TEXT_OFFSET was enabled. Since that
alignment has been removed and _text is used to map the .text segment,
we need ensure _text is always page aligned when RANDOMIZE_TEXT_OFFSET
is enabled.

This patch adds logic to TEXT_OFFSET fuzzing to ensure that the offset
is always aligned to the kernel page size. To ensure this, we rely on
the PAGE_SHIFT being available via Kconfig.

Signed-off-by: Mark Rutland <[email protected]>
Reported-by: Sudeep Holla <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Fixes: 7eb90f2 ("arm64: cover the .head.text section in the .text segment mapping")
Signed-off-by: Will Deacon <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
…offline_kmem()

memcg_offline_kmem() may be called from memcg_free_kmem() after a css
init failure.  memcg_free_kmem() is a ->css_free callback which is
called without cgroup_mutex and memcg_offline_kmem() ends up using
css_for_each_descendant_pre() without any locking.  Fix it by adding rcu
read locking around it.

    mkdir: cannot create directory `65530': No space left on device
    ===============================
    [ INFO: suspicious RCU usage. ]
    4.6.0-work+ torvalds#321 Not tainted
    -------------------------------
    kernel/cgroup.c:4008 cgroup_mutex or RCU read lock required!
     [  527.243970] other info that might help us debug this:
     [  527.244715]
    rcu_scheduler_active = 1, debug_locks = 0
    2 locks held by kworker/0:5/1664:
     #0:  ("cgroup_destroy"){.+.+..}, at: [<ffffffff81060ab5>] process_one_work+0x165/0x4a0
     #1:  ((&css->destroy_work)#3){+.+...}, at: [<ffffffff81060ab5>] process_one_work+0x165/0x4a0
     [  527.248098] stack backtrace:
    CPU: 0 PID: 1664 Comm: kworker/0:5 Not tainted 4.6.0-work+ torvalds#321
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.1-1.fc24 04/01/2014
    Workqueue: cgroup_destroy css_free_work_fn
    Call Trace:
      dump_stack+0x68/0xa1
      lockdep_rcu_suspicious+0xd7/0x110
      css_next_descendant_pre+0x7d/0xb0
      memcg_offline_kmem.part.44+0x4a/0xc0
      mem_cgroup_css_free+0x1ec/0x200
      css_free_work_fn+0x49/0x5e0
      process_one_work+0x1c5/0x4a0
      worker_thread+0x49/0x490
      kthread+0xea/0x100
      ret_from_fork+0x1f/0x40

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Tejun Heo <[email protected]>
Acked-by: Vladimir Davydov <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: <[email protected]>	[4.5+]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
One of the debian buildd servers had this crash in the syslog without
any other information:

 Unaligned handler failed, ret = -2
 clock_adjtime (pid 22578): Unaligned data reference (code 28)
 CPU: 1 PID: 22578 Comm: clock_adjtime Tainted: G  E  4.5.0-2-parisc64-smp #1 Debian 4.5.4-1
 task: 000000007d9960f8 ti: 00000001bde7c000 task.ti: 00000001bde7c000

      YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
 PSW: 00001000000001001111100000001111 Tainted: G            E
 r00-03  000000ff0804f80f 00000001bde7c2b0 00000000402d2be8 00000001bde7c2b0
 r04-07  00000000409e1fd0 00000000fa6f7fff 00000001bde7c148 00000000fa6f7fff
 r08-11  0000000000000000 00000000ffffffff 00000000fac9bb7b 000000000002b4d4
 r12-15  000000000015241c 000000000015242c 000000000000002d 00000000fac9bb7b
 r16-19  0000000000028800 0000000000000001 0000000000000070 00000001bde7c218
 r20-23  0000000000000000 00000001bde7c210 0000000000000002 0000000000000000
 r24-27  0000000000000000 0000000000000000 00000001bde7c148 00000000409e1fd0
 r28-31  0000000000000001 00000001bde7c320 00000001bde7c350 00000001bde7c218
 sr00-03  0000000001200000 0000000001200000 0000000000000000 0000000001200000
 sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000402d2e84 00000000402d2e88
  IIR: 0ca0d089    ISR: 0000000001200000  IOR: 00000000fa6f7fff
  CPU:        1   CR30: 00000001bde7c000 CR31: ffffffffffffffff
  ORIG_R28: 00000002369fe628
  IAOQ[0]: compat_get_timex+0x2dc/0x3c0
  IAOQ[1]: compat_get_timex+0x2e0/0x3c0
  RP(r2): compat_get_timex+0x40/0x3c0
 Backtrace:
  [<00000000402d4608>] compat_SyS_clock_adjtime+0x40/0xc0
  [<0000000040205024>] syscall_exit+0x0/0x14

This means the userspace program clock_adjtime called the clock_adjtime()
syscall and then crashed inside the compat_get_timex() function.
Syscalls should never crash programs, but instead return EFAULT.

The IIR register contains the executed instruction, which disassebles
into "ldw 0(sr3,r5),r9".
This load-word instruction is part of __get_user() which tried to read the word
at %r5/IOR (0xfa6f7fff). This means the unaligned handler jumped in.  The
unaligned handler is able to emulate all ldw instructions, but it fails if it
fails to read the source e.g. because of page fault.

The following program reproduces the problem:

#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/mman.h>

int main(void) {
        /* allocate 8k */
        char *ptr = mmap(NULL, 2*4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
        /* free second half (upper 4k) and make it invalid. */
        munmap(ptr+4096, 4096);
        /* syscall where first int is unaligned and clobbers into invalid memory region */
        /* syscall should return EFAULT */
        return syscall(__NR_clock_adjtime, 0, ptr+4095);
}

To fix this issue we simply need to check if the faulting instruction address
is in the exception fixup table when the unaligned handler failed. If it
is, call the fixup routine instead of crashing.

While looking at the unaligned handler I found another issue as well: The
target register should not be modified if the handler was unsuccessful.

Signed-off-by: Helge Deller <[email protected]>
Cc: [email protected]
hgn pushed a commit that referenced this pull request Jun 14, 2016
The police action is using its own code to initialize tcf hash
info, which makes us to forgot to initialize a->hinfo correctly.
Fix this by calling the helper function tcf_hash_create() directly.

This patch fixed the following crash:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
 IP: [<ffffffff810c099f>] __lock_acquire+0xd3/0xf91
 PGD d3c34067 PUD d3e18067 PMD 0
 Oops: 0000 [#1] SMP
 CPU: 2 PID: 853 Comm: tc Not tainted 4.6.0+ torvalds#87
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 task: ffff8800d3e28040 ti: ffff8800d3f6c000 task.ti: ffff8800d3f6c000
 RIP: 0010:[<ffffffff810c099f>]  [<ffffffff810c099f>] __lock_acquire+0xd3/0xf91
 RSP: 0000:ffff88011b203c80  EFLAGS: 00010002
 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000028
 RBP: ffff88011b203d40 R08: 0000000000000001 R09: 0000000000000000
 R10: ffff88011b203d58 R11: ffff88011b208000 R12: 0000000000000001
 R13: ffff8800d3e28040 R14: 0000000000000028 R15: 0000000000000000
 FS:  0000000000000000(0000) GS:ffff88011b200000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000028 CR3: 00000000d4be1000 CR4: 00000000000006e0
 Stack:
  ffff8800d3e289c0 0000000000000046 000000001b203d60 ffffffff00000000
  0000000000000000 ffff880000000000 0000000000000000 ffffffff00000000
  ffffffff8187142c ffff88011b203ce8 ffff88011b203ce8 ffffffff8101dbfc
 Call Trace:
  <IRQ>
  [<ffffffff8187142c>] ? __tcf_hash_release+0x77/0xd1
  [<ffffffff8101dbfc>] ? native_sched_clock+0x1a/0x35
  [<ffffffff8101dbfc>] ? native_sched_clock+0x1a/0x35
  [<ffffffff810a9604>] ? sched_clock_local+0x11/0x78
  [<ffffffff810bf6a1>] ? mark_lock+0x24/0x201
  [<ffffffff810c1dbd>] lock_acquire+0x120/0x1b4
  [<ffffffff810c1dbd>] ? lock_acquire+0x120/0x1b4
  [<ffffffff8187142c>] ? __tcf_hash_release+0x77/0xd1
  [<ffffffff81aad89f>] _raw_spin_lock_bh+0x3c/0x72
  [<ffffffff8187142c>] ? __tcf_hash_release+0x77/0xd1
  [<ffffffff8187142c>] __tcf_hash_release+0x77/0xd1
  [<ffffffff81871a27>] tcf_action_destroy+0x49/0x7c
  [<ffffffff81870b1c>] tcf_exts_destroy+0x20/0x2d
  [<ffffffff8189273b>] u32_destroy_key+0x1b/0x4d
  [<ffffffff81892788>] u32_delete_key_freepf_rcu+0x1b/0x1d
  [<ffffffff810de3b8>] rcu_process_callbacks+0x610/0x82e
  [<ffffffff8189276d>] ? u32_destroy_key+0x4d/0x4d
  [<ffffffff81ab0bc1>] __do_softirq+0x191/0x3f4

Fixes: ddf97cc ("net_sched: add network namespace support for tc actions")
Cc: Jamal Hadi Salim <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
Unused fields of udp_cfg must be all zeros. Otherwise
setup_udp_tunnel_sock() fills ->gro_receive and ->gro_complete
callbacks with garbage, eventually resulting in panic when used by
udp_gro_receive().

[   72.694123] BUG: unable to handle kernel paging request at ffff880033f87d78
[   72.695518] IP: [<ffff880033f87d78>] 0xffff880033f87d78
[   72.696530] PGD 26e2067 PUD 26e3067 PMD 342ed063 PTE 8000000033f87163
[   72.696530] Oops: 0011 [#1] SMP KASAN
[   72.696530] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core ip6_udp_tunnel udp_tunnel pptp gre pppox ppp_generic slhc crc32c_intel ghash_clmulni_intel jitterentropy_rng sha256_generic hmac drbg ansi_cprng aesni_intel evdev aes_x86_64 ablk_helper cryptd lrw gf128mul glue_helper serio_raw acpi_cpufreq button proc\
essor ext4 crc16 jbd2 mbcache virtio_blk virtio_net virtio_pci virtio_ring virtio
[   72.696530] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.7.0-rc1 #1
[   72.696530] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[   72.696530] task: ffff880035b59700 ti: ffff880035b70000 task.ti: ffff880035b70000
[   72.696530] RIP: 0010:[<ffff880033f87d78>]  [<ffff880033f87d78>] 0xffff880033f87d78
[   72.696530] RSP: 0018:ffff880035f87bc0  EFLAGS: 00010246
[   72.696530] RAX: ffffed000698f996 RBX: ffff88003326b840 RCX: ffffffff814cc823
[   72.696530] RDX: ffff88003326b840 RSI: ffff880033e48038 RDI: ffff880034c7c780
[   72.696530] RBP: ffff880035f87c18 R08: 000000000000a506 R09: 0000000000000000
[   72.696530] R10: ffff880035f87b38 R11: ffff880034b9344d R12: 00000000ebfea715
[   72.696530] R13: 0000000000000000 R14: ffff880034c7c780 R15: 0000000000000000
[   72.696530] FS:  0000000000000000(0000) GS:ffff880035f80000(0000) knlGS:0000000000000000
[   72.696530] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   72.696530] CR2: ffff880033f87d78 CR3: 0000000033c98000 CR4: 00000000000406a0
[   72.696530] Stack:
[   72.696530]  ffffffff814cc834 ffff880034b93468 0000001481416818 ffff88003326b874
[   72.696530]  ffff880034c7ccb0 ffff880033e48038 ffff88003326b840 ffff880034b93462
[   72.696530]  ffff88003326b88a ffff88003326b88c ffff880034b93468 ffff880035f87c70
[   72.696530] Call Trace:
[   72.696530]  <IRQ>
[   72.696530]  [<ffffffff814cc834>] ? udp_gro_receive+0x1c6/0x1f9
[   72.696530]  [<ffffffff814ccb1c>] udp4_gro_receive+0x2b5/0x310
[   72.696530]  [<ffffffff814d989b>] inet_gro_receive+0x4a3/0x4cd
[   72.696530]  [<ffffffff81431b32>] dev_gro_receive+0x584/0x7a3
[   72.696530]  [<ffffffff810adf7a>] ? __lock_is_held+0x29/0x64
[   72.696530]  [<ffffffff814321f7>] napi_gro_receive+0x124/0x21d
[   72.696530]  [<ffffffffa000b145>] virtnet_receive+0x8df/0x8f6 [virtio_net]
[   72.696530]  [<ffffffffa000b27e>] virtnet_poll+0x1d/0x8d [virtio_net]
[   72.696530]  [<ffffffff81431350>] net_rx_action+0x15b/0x3b9
[   72.696530]  [<ffffffff815893d6>] __do_softirq+0x216/0x546
[   72.696530]  [<ffffffff81062392>] irq_exit+0x49/0xb6
[   72.696530]  [<ffffffff81588e9a>] do_IRQ+0xe2/0xfa
[   72.696530]  [<ffffffff81587a49>] common_interrupt+0x89/0x89
[   72.696530]  <EOI>
[   72.696530]  [<ffffffff810b05df>] ? trace_hardirqs_on_caller+0x229/0x270
[   72.696530]  [<ffffffff8102b3c7>] ? default_idle+0x1c/0x2d
[   72.696530]  [<ffffffff8102b3c5>] ? default_idle+0x1a/0x2d
[   72.696530]  [<ffffffff8102bb8c>] arch_cpu_idle+0xa/0xc
[   72.696530]  [<ffffffff810a6c39>] default_idle_call+0x1a/0x1c
[   72.696530]  [<ffffffff810a6d96>] cpu_startup_entry+0x15b/0x20f
[   72.696530]  [<ffffffff81039a81>] start_secondary+0x12c/0x133
[   72.696530] Code: ff ff ff ff ff ff ff ff ff ff 7f ff ff ff ff ff ff ff 7f 00 7e f8 33 00 88 ff ff 6d 61 58 81 ff ff ff ff 5e de 0a 81 ff ff ff ff <00> 5c e2 34 00 88 ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00
[   72.696530] RIP  [<ffff880033f87d78>] 0xffff880033f87d78
[   72.696530]  RSP <ffff880035f87bc0>
[   72.696530] CR2: ffff880033f87d78
[   72.696530] ---[ end trace ad7758b9a1dccf99 ]---
[   72.696530] Kernel panic - not syncing: Fatal exception in interrupt
[   72.696530] Kernel Offset: disabled
[   72.696530] ---[ end Kernel panic - not syncing: Fatal exception in interrupt

v2: use empty initialiser instead of "{ NULL }" to avoid relying on
    first field's type.

Fixes: 38fd2af ("udp: Add socket based GRO and config")
Signed-off-by: Guillaume Nault <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
hgn pushed a commit that referenced this pull request Jun 14, 2016
Zi Shen Lim says:

====================
arm64 BPF JIT updates

Updates for arm64 eBPF JIT.
The main addition here is implementation of bpf_tail_call.

Changes since v2:
 - None. Resubmit per David Miller.

Changes since v1:
 - Added patch #1 to address build error due to missing header inclusion
   in linux/bpf.h. (Thanks to suggestion and ack by Daniel Borkmann)
   Ordered it ahead of bpf_tail_call patch #2 so build error is not
   triggered.
====================

Signed-off-by: David S. Miller <[email protected]>
hgn pushed a commit that referenced this pull request Jan 29, 2020
With zpci_disable() working, lockdep detected a potential deadlock
(lockdep output at the end).

The deadlock is between recovering a PCI function via the

/sys/bus/pci/devices/<dev>/recover

attribute vs powering it off via

/sys/bus/pci/slots/<slot>/power.

The fix is analogous to the changes in commit 0ee223b ("scsi: core:
Avoid that SCSI device removal through sysfs triggers a deadlock")
that fixed a potential deadlock on removing a SCSI device via sysfs.

[  204.830107] ======================================================
[  204.830109] WARNING: possible circular locking dependency detected
[  204.830111] 5.5.0-rc2-06072-gbc03ecc9a672 #6 Tainted: G        W
[  204.830112] ------------------------------------------------------
[  204.830113] bash/1034 is trying to acquire lock:
[  204.830115] 0000000192a1a610 (kn->count#200){++++}, at: kernfs_remove_by_name_ns+0x5c/0xa8
[  204.830122]
               but task is already holding lock:
[  204.830123] 00000000c16134a8 (pci_rescan_remove_lock){+.+.}, at: pci_stop_and_remove_bus_device_locked+0x26/0x48
[  204.830128]
               which lock already depends on the new lock.

[  204.830129]
               the existing dependency chain (in reverse order) is:
[  204.830130]
               -> #1 (pci_rescan_remove_lock){+.+.}:
[  204.830134]        validate_chain+0x93a/0xd08
[  204.830136]        __lock_acquire+0x4ae/0x9d0
[  204.830137]        lock_acquire+0x114/0x280
[  204.830140]        __mutex_lock+0xa2/0x960
[  204.830142]        mutex_lock_nested+0x32/0x40
[  204.830145]        recover_store+0x4c/0xa8
[  204.830147]        kernfs_fop_write+0xe6/0x218
[  204.830151]        vfs_write+0xb0/0x1b8
[  204.830152]        ksys_write+0x6c/0xf8
[  204.830154]        system_call+0xd8/0x2d8
[  204.830155]
               -> #0 (kn->count#200){++++}:
[  204.830187]        check_noncircular+0x1e6/0x240
[  204.830189]        check_prev_add+0xfc/0xdb0
[  204.830190]        validate_chain+0x93a/0xd08
[  204.830192]        __lock_acquire+0x4ae/0x9d0
[  204.830193]        lock_acquire+0x114/0x280
[  204.830194]        __kernfs_remove.part.0+0x2e4/0x360
[  204.830196]        kernfs_remove_by_name_ns+0x5c/0xa8
[  204.830198]        remove_files.isra.0+0x4c/0x98
[  204.830199]        sysfs_remove_group+0x66/0xc8
[  204.830201]        sysfs_remove_groups+0x46/0x68
[  204.830204]        device_remove_attrs+0x52/0x90
[  204.830207]        device_del+0x182/0x418
[  204.830208]        pci_remove_bus_device+0x8a/0x130
[  204.830210]        pci_stop_and_remove_bus_device_locked+0x3a/0x48
[  204.830212]        disable_slot+0x68/0x100
[  204.830213]        power_write_file+0x7c/0x130
[  204.830215]        kernfs_fop_write+0xe6/0x218
[  204.830217]        vfs_write+0xb0/0x1b8
[  204.830218]        ksys_write+0x6c/0xf8
[  204.830220]        system_call+0xd8/0x2d8
[  204.830221]
               other info that might help us debug this:

[  204.830223]  Possible unsafe locking scenario:

[  204.830224]        CPU0                    CPU1
[  204.830225]        ----                    ----
[  204.830226]   lock(pci_rescan_remove_lock);
[  204.830227]                                lock(kn->count#200);
[  204.830229]                                lock(pci_rescan_remove_lock);
[  204.830231]   lock(kn->count#200);
[  204.830233]
                *** DEADLOCK ***

[  204.830234] 4 locks held by bash/1034:
[  204.830235]  #0: 00000001b6fbc498 (sb_writers#4){.+.+}, at: vfs_write+0x158/0x1b8
[  204.830239]  #1: 000000018c9f5090 (&of->mutex){+.+.}, at: kernfs_fop_write+0xaa/0x218
[  204.830242]  #2: 00000001f7da0810 (kn->count#235){.+.+}, at: kernfs_fop_write+0xb6/0x218
[  204.830245]  #3: 00000000c16134a8 (pci_rescan_remove_lock){+.+.}, at: pci_stop_and_remove_bus_device_locked+0x26/0x48
[  204.830248]
               stack backtrace:
[  204.830250] CPU: 2 PID: 1034 Comm: bash Tainted: G        W         5.5.0-rc2-06072-gbc03ecc9a672 #6
[  204.830252] Hardware name: IBM 8561 T01 703 (LPAR)
[  204.830253] Call Trace:
[  204.830257]  [<00000000c05e10c0>] show_stack+0x88/0xf0
[  204.830260]  [<00000000c112dca4>] dump_stack+0xa4/0xe0
[  204.830261]  [<00000000c0694c06>] check_noncircular+0x1e6/0x240
[  204.830263]  [<00000000c0695bec>] check_prev_add+0xfc/0xdb0
[  204.830264]  [<00000000c06971da>] validate_chain+0x93a/0xd08
[  204.830266]  [<00000000c06994c6>] __lock_acquire+0x4ae/0x9d0
[  204.830267]  [<00000000c069867c>] lock_acquire+0x114/0x280
[  204.830269]  [<00000000c09ca15c>] __kernfs_remove.part.0+0x2e4/0x360
[  204.830270]  [<00000000c09cb5c4>] kernfs_remove_by_name_ns+0x5c/0xa8
[  204.830272]  [<00000000c09cee14>] remove_files.isra.0+0x4c/0x98
[  204.830274]  [<00000000c09cf2ae>] sysfs_remove_group+0x66/0xc8
[  204.830276]  [<00000000c09cf356>] sysfs_remove_groups+0x46/0x68
[  204.830278]  [<00000000c0e3dfe2>] device_remove_attrs+0x52/0x90
[  204.830280]  [<00000000c0e40382>] device_del+0x182/0x418
[  204.830281]  [<00000000c0dcfd7a>] pci_remove_bus_device+0x8a/0x130
[  204.830283]  [<00000000c0dcfe92>] pci_stop_and_remove_bus_device_locked+0x3a/0x48
[  204.830285]  [<00000000c0de7190>] disable_slot+0x68/0x100
[  204.830286]  [<00000000c0de6514>] power_write_file+0x7c/0x130
[  204.830288]  [<00000000c09cc846>] kernfs_fop_write+0xe6/0x218
[  204.830290]  [<00000000c08f3480>] vfs_write+0xb0/0x1b8
[  204.830291]  [<00000000c08f378c>] ksys_write+0x6c/0xf8
[  204.830293]  [<00000000c1154374>] system_call+0xd8/0x2d8
[  204.830294] INFO: lockdep is turned off.

Signed-off-by: Niklas Schnelle <[email protected]>
Reviewed-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>
hgn pushed a commit that referenced this pull request Jan 29, 2020
Since commit:

  d44f1b8 ("arm64: KVM/mm: Move SEA handling behind a single 'claim' interface")

... the top-level APEI SEA handler has the shape:

1. current_flags = arch_local_save_flags()
2. local_daif_restore(DAIF_ERRCTX)
3. <GHES handler>
4. local_daif_restore(current_flags)

However, since commit:

  4a50321 ("arm64: irqflags: Use ICC_PMR_EL1 for interrupt masking")

... when pseudo-NMIs (pNMIs) are in use, arch_local_save_flags() will save
the PMR value rather than the DAIF flags.

The combination of these two commits means that the APEI SEA handler will
erroneously attempt to restore the PMR value into DAIF. Fix this by
factoring local_daif_save_flags() out of local_daif_save(), so that we
can consistently save DAIF in step #1, regardless of whether pNMIs are in
use.

Both commits were introduced concurrently in v5.0.

Cc: <[email protected]>
Fixes: 4a50321 ("arm64: irqflags: Use ICC_PMR_EL1 for interrupt masking")
Fixes: d44f1b8 ("arm64: KVM/mm: Move SEA handling behind a single 'claim' interface")
Signed-off-by: Mark Rutland <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: James Morse <[email protected]>
Cc: Julien Thierry <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
hgn pushed a commit that referenced this pull request Jan 29, 2020
Commit 0034d39 ("powerpc/mm/hash64: Map all the kernel regions in
the same 0xc range") has a bug in the definition of MIN_USER_CONTEXT.

The result is that the context id used for the vmemmap and the lowest
context id handed out to userspace are the same. The context id is
essentially the process identifier as far as the first stage of the
MMU translation is concerned.

This can result in multiple SLB entries with the same VSID (Virtual
Segment ID), accessible to the kernel and some random userspace
process that happens to get the overlapping id, which is not expected
eg:

  07 c00c000008000000 40066bdea7000500  1T  ESID=   c00c00  VSID=      66bdea7 LLP:100
  12 0002000008000000 40066bdea7000d80  1T  ESID=      200  VSID=      66bdea7 LLP:100

Even though the user process and the kernel use the same VSID, the
permissions in the hash page table prevent the user process from
reading or writing to any kernel mappings.

It can also lead to SLB entries with different base page size
encodings (LLP), eg:

  05 c00c000008000000 00006bde0053b500 256M ESID=c00c00000  VSID=    6bde0053b LLP:100
  09 0000000008000000 00006bde0053bc80 256M ESID=        0  VSID=    6bde0053b LLP:  0

Such SLB entries can result in machine checks, eg. as seen on a G5:

  Oops: Machine check, sig: 7 [#1]
  BE PAGE SIZE=64K MU-Hash SMP NR_CPUS=4 NUMA Power Mac
  NIP: c00000000026f248 LR: c000000000295e58 CTR: 0000000000000000
  REGS: c0000000erfd3d70 TRAP: 0200 Tainted: G M (5.5.0-rcl-gcc-8.2.0-00010-g228b667d8ea1)
  MSR: 9000000000109032 <SF,HV,EE,ME,IR,DR,RI> CR: 24282048 XER: 00000000
  DAR: c00c000000612c80 DSISR: 00000400 IRQMASK: 0
  ...
  NIP [c00000000026f248] .kmem_cache_free+0x58/0x140
  LR  [c088000008295e58] .putname 8x88/0xa
  Call Trace:
    .putname+0xB8/0xa
    .filename_lookup.part.76+0xbe/0x160
    .do_faccessat+0xe0/0x380
    system_call+0x5c/ex68

This happens with 256MB segments and 64K pages, as the duplicate VSID
is hit with the first vmemmap segment and the first user segment, and
older 32-bit userspace maps things in the first user segment.

On other CPUs a machine check is not seen. Instead the userspace
process can get stuck continuously faulting, with the fault never
properly serviced, due to the kernel not understanding that there is
already a HPTE for the address but with inaccessible permissions.

On machines with 1T segments we've not seen the bug hit other than by
deliberately exercising it. That seems to be just a matter of luck
though, due to the typical layout of the user virtual address space
and the ranges of vmemmap that are typically populated.

To fix it we add 2 to MIN_USER_CONTEXT. This ensures the lowest
context given to userspace doesn't overlap with the VMEMMAP context,
or with the context for INVALID_REGION_ID.

Fixes: 0034d39 ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
Cc: [email protected] # v5.2+
Reported-by: Christian Marillat <[email protected]>
Reported-by: Romain Dolbeau <[email protected]>
Signed-off-by: Aneesh Kumar K.V <[email protected]>
[mpe: Account for INVALID_REGION_ID, mostly rewrite change log]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
hgn pushed a commit that referenced this pull request Jan 29, 2020
Gautam Ramakrishnan says:

====================
net: sched: add Flow Queue PIE packet scheduler

Flow Queue PIE packet scheduler

This patch series implements the Flow Queue Proportional
Integral controller Enhanced (FQ-PIE) active queue
Management algorithm. It is an enhancement over the PIE
algorithm. It integrates the PIE aqm with a deficit round robin
scheme.

FQ-PIE is implemented over the latest version of PIE which
uses timestamps to calculate queue delay with an additional
option of using average dequeue rate to calculate the queue
delay. This patch also adds a memory limit of all the packets
across all queues to a default value of 32Mb.

 - Patch #1
   - Creates pie.h and moves all small functions and structures
     common to PIE and FQ-PIE here. The functions are all made
     inline.
 - Patch #2 - #8
   - Addresses code formatting, indentation, comment changes
     and rearrangement of structure members.
 - Patch torvalds#9
   - Refactors sch_pie.c by changing arguments to
     calculate_probability(), [pie_]drop_early() and
     pie_process_dequeue() to make it generic enough to
     be used by sch_fq_pie.c. These functions are exported
     to be used by sch_fq_pie.c.
 - Patch torvalds#10
   - Adds the FQ-PIE Qdisc.

For more information:
https://tools.ietf.org/html/rfc8033

Changes from v6 to v7
 - Call tcf_block_put() when destroying the Qdisc as suggested
   by Jakub Kicinski.

Changes from v5 to v6
 - Rearranged struct members according to their access pattern
   and to remove holes.

Changes from v4 to v5
 - This patch series breaks down patch 1 of v4 into
   separate logical commits as suggested by David Miller.

Changes from v3 to v4
 - Used non deprecated version of nla_parse_nested
 - Used SZ_32M macro
 - Removed an unused variable
 - Code cleanup
 All suggested by Jakub and Toke.

Changes from v2 to v3
 - Exported drop_early, pie_process_dequeue and
   calculate_probability functions from sch_pie as
   suggested by Stephen Hemminger.

Changes from v1 ( and RFC patch) to v2
 - Added timestamp to calculate queue delay as recommended
   by Dave Taht
 - Packet memory limit implemented as recommended by Toke.
 - Added external classifier as recommended by Toke.
 - Used NET_XMIT_CN instead of NET_XMIT_DROP as the return
   value in the fq_pie_qdisc_enqueue function.
====================

Signed-off-by: David S. Miller <[email protected]>
hgn pushed a commit that referenced this pull request Jan 29, 2020
We don't need to hold the local pinctrl lock here to set irq wake on the
summary irq line. Doing so only leads to lockdep warnings instead of
protecting us from anything. Remove the locking.

 WARNING: possible circular locking dependency detected
 5.4.11 #2 Tainted: G        W
 ------------------------------------------------------
 cat/3083 is trying to acquire lock:
 ffffff81f4fa58c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94

 but task is already holding lock:
 ffffff81f4880c18 (&pctrl->lock){-.-.}, at: msm_gpio_irq_set_wake+0x48/0x7c

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (&pctrl->lock){-.-.}:
        _raw_spin_lock_irqsave+0x64/0x80
        msm_gpio_irq_ack+0x68/0xf4
        __irq_do_set_handler+0xe0/0x180
        __irq_set_handler+0x60/0x9c
        irq_domain_set_info+0x90/0xb4
        gpiochip_hierarchy_irq_domain_alloc+0x110/0x200
        __irq_domain_alloc_irqs+0x130/0x29c
        irq_create_fwspec_mapping+0x1f0/0x300
        irq_create_of_mapping+0x70/0x98
        of_irq_get+0xa4/0xd4
        spi_drv_probe+0x4c/0xb0
        really_probe+0x138/0x3f0
        driver_probe_device+0x70/0x140
        __device_attach_driver+0x9c/0x110
        bus_for_each_drv+0x88/0xd0
        __device_attach+0xb0/0x160
        device_initial_probe+0x20/0x2c
        bus_probe_device+0x34/0x94
        device_add+0x35c/0x3f0
        spi_add_device+0xbc/0x194
        of_register_spi_devices+0x2c8/0x408
        spi_register_controller+0x57c/0x6fc
        spi_geni_probe+0x260/0x328
        platform_drv_probe+0x90/0xb0
        really_probe+0x138/0x3f0
        driver_probe_device+0x70/0x140
        device_driver_attach+0x4c/0x6c
        __driver_attach+0xcc/0x154
        bus_for_each_dev+0x84/0xcc
        driver_attach+0x2c/0x38
        bus_add_driver+0x108/0x1fc
        driver_register+0x64/0xf8
        __platform_driver_register+0x4c/0x58
        spi_geni_driver_init+0x1c/0x24
        do_one_initcall+0x1a4/0x3e8
        do_initcall_level+0xb4/0xcc
        do_basic_setup+0x30/0x48
        kernel_init_freeable+0x124/0x1a8
        kernel_init+0x14/0x100
        ret_from_fork+0x10/0x18

 -> #0 (&irq_desc_lock_class){-.-.}:
        __lock_acquire+0xeb4/0x2388
        lock_acquire+0x1cc/0x210
        _raw_spin_lock_irqsave+0x64/0x80
        __irq_get_desc_lock+0x64/0x94
        irq_set_irq_wake+0x40/0x144
        msm_gpio_irq_set_wake+0x5c/0x7c
        set_irq_wake_real+0x40/0x5c
        irq_set_irq_wake+0x70/0x144
        cros_ec_rtc_suspend+0x38/0x4c
        platform_pm_suspend+0x34/0x60
        dpm_run_callback+0x64/0xcc
        __device_suspend+0x310/0x41c
        dpm_suspend+0xf8/0x298
        dpm_suspend_start+0x84/0xb4
        suspend_devices_and_enter+0xbc/0x620
        pm_suspend+0x210/0x348
        state_store+0xb0/0x108
        kobj_attr_store+0x14/0x24
        sysfs_kf_write+0x4c/0x64
        kernfs_fop_write+0x15c/0x1fc
        __vfs_write+0x54/0x18c
        vfs_write+0xe4/0x1a4
        ksys_write+0x7c/0xe4
        __arm64_sys_write+0x20/0x2c
        el0_svc_common+0xa8/0x160
        el0_svc_handler+0x7c/0x98
        el0_svc+0x8/0xc

 other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&pctrl->lock);
                                lock(&irq_desc_lock_class);
                                lock(&pctrl->lock);
   lock(&irq_desc_lock_class);

  *** DEADLOCK ***

 7 locks held by cat/3083:
  #0: ffffff81f06d1420 (sb_writers#7){.+.+}, at: vfs_write+0xd0/0x1a4
  #1: ffffff81c8935680 (&of->mutex){+.+.}, at: kernfs_fop_write+0x12c/0x1fc
  #2: ffffff81f4c322f0 (kn->count#337){.+.+}, at: kernfs_fop_write+0x134/0x1fc
  #3: ffffffe89a641d60 (system_transition_mutex){+.+.}, at: pm_suspend+0x108/0x348
  #4: ffffff81f190e970 (&dev->mutex){....}, at: __device_suspend+0x168/0x41c
  #5: ffffff81f183d8c0 (lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94
  #6: ffffff81f4880c18 (&pctrl->lock){-.-.}, at: msm_gpio_irq_set_wake+0x48/0x7c

 stack backtrace:
 CPU: 4 PID: 3083 Comm: cat Tainted: G        W         5.4.11 #2
 Hardware name: Google Cheza (rev3+) (DT)
 Call trace:
  dump_backtrace+0x0/0x174
  show_stack+0x20/0x2c
  dump_stack+0xc8/0x124
  print_circular_bug+0x2ac/0x2c4
  check_noncircular+0x1a0/0x1a8
  __lock_acquire+0xeb4/0x2388
  lock_acquire+0x1cc/0x210
  _raw_spin_lock_irqsave+0x64/0x80
  __irq_get_desc_lock+0x64/0x94
  irq_set_irq_wake+0x40/0x144
  msm_gpio_irq_set_wake+0x5c/0x7c
  set_irq_wake_real+0x40/0x5c
  irq_set_irq_wake+0x70/0x144
  cros_ec_rtc_suspend+0x38/0x4c
  platform_pm_suspend+0x34/0x60
  dpm_run_callback+0x64/0xcc
  __device_suspend+0x310/0x41c
  dpm_suspend+0xf8/0x298
  dpm_suspend_start+0x84/0xb4
  suspend_devices_and_enter+0xbc/0x620
  pm_suspend+0x210/0x348
  state_store+0xb0/0x108
  kobj_attr_store+0x14/0x24
  sysfs_kf_write+0x4c/0x64
  kernfs_fop_write+0x15c/0x1fc
  __vfs_write+0x54/0x18c
  vfs_write+0xe4/0x1a4
  ksys_write+0x7c/0xe4
  __arm64_sys_write+0x20/0x2c
  el0_svc_common+0xa8/0x160
  el0_svc_handler+0x7c/0x98
  el0_svc+0x8/0xc

Fixes: 6aced33 ("pinctrl: msm: drop wake_irqs bitmap")
Cc: Douglas Anderson <[email protected]>
Cc: Brian Masney <[email protected]>
Cc: Lina Iyer <[email protected]>
Cc: Maulik Shah <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Bjorn Andersson <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
hgn pushed a commit that referenced this pull request Jan 29, 2020
Ido Schimmel says:

====================
mlxsw: Offload TBF

Petr says:

In order to allow configuration of shapers on Spectrum family of
machines, recognize TBF either as root Qdisc, or as a child of ETS or
PRIO. Configure rate of maximum shaper according to TBF rate setting,
and maximum shaper burst size according to TBF burst setting.

- Patches #1 and #2 make the TBF shaper suitable for offloading.
- Patches #3, #4 and #5 are refactoring aimed at easier support of leaf
  Qdiscs in general.
- Patches #6 to torvalds#10 gradually introduce TBF offload.
- Patches torvalds#11 to torvalds#14 add selftests.
====================

Signed-off-by: David S. Miller <[email protected]>
hgn pushed a commit that referenced this pull request Jan 29, 2020
When simulate random transfer fail for sdio write and read, it crash
sometimes.

Test steps:
1. Add config and update kernel:
CONFIG_FAIL_MMC_REQUEST=y
CONFIG_FAULT_INJECTION=y
CONFIG_FAULT_INJECTION_DEBUG_FS=y

2. run simulate fail:
cd /sys/kernel/debug/mmc1/fail_mmc_request
echo 10 > probability
echo 10 > times # repeat until hitting issues

3. it crash, the act len of ath10k_htc_hdr is higher than allocate len, it cause panic:
[   99.723482] skbuff: skb_over_panic: text:00000000caa0f780 len:57013 put:57013 head:000000004116f24a data:0000000019ecb4dc tail:0xdef5 end:0x640 dev:<NULL>
[   99.737697] ------------[ cut here ]------------
[   99.742327] kernel BUG at /mnt/host/source/src/third_party/kernel/v4.19/net/core/skbuff.c:104!
[   99.750937] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
[   99.831154] Process kworker/0:2 (pid: 151, stack limit = 0x00000000728010bf)
[   99.838200] CPU: 0 PID: 151 Comm: kworker/0:2 Tainted: G W 4.19.85 torvalds#48
[   99.846022] Hardware name: MediaTek krane sku0 board (DT)
[   99.851429] Workqueue: events sdio_irq_work
[   99.855614] pstate: 60000005 (nZCv daif -PAN -UAO)
[   99.860402] pc : skb_panic+0x64/0x68
[   99.863974] lr : skb_panic+0x64/0x68
[   99.867542] sp : ffffff8008833a90
[   99.870850] x29: ffffff8008833ac0 x28: ffffffe52e337370
[   99.876159] x27: ffffffe52e328a90 x26: 000000000000e0d0
[   99.881469] x25: ffffffe52e336b60 x24: 000000000000deb5
[   99.886779] x23: ffffffe52e340680 x22: ffffffe4efd47e00
[   99.892088] x21: 000000000000deb5 x20: ffffffa516d85b4c
[   99.897397] x19: ffffffa526928037 x18: 0000000000000000
[   99.902706] x17: 000000000000003c x16: ffffffa5265b6c80
[   99.908015] x15: 0000000000000006 x14: 3a76656420303436
[   99.913325] x13: 0000000000029bf0 x12: 0000000000000000
[   99.918634] x11: 0000000000000000 x10: 0000000000000000
[   99.923943] x9 : a3b907e4b2783000 x8 : a3b907e4b2783000
[   99.929253] x7 : 0000000000000000 x6 : ffffffa526f66d76
[   99.934563] x5 : 0000000000000000 x4 : 0000000000000000
[   99.939872] x3 : 000000000002a5ab x2 : ffffffe53feed918
[   99.945182] x1 : ffffffe53fee4a08 x0 : 000000000000008e
[   99.950491] Call trace:
[   99.952937]  skb_panic+0x64/0x68
[   99.956165]  skb_put+0x7c/0x84
[   99.959224]  ath10k_sdio_irq_handler+0x740/0xbb8 [ath10k_sdio]
[   99.965055]  process_sdio_pending_irqs+0x58/0x1a4
[   99.969758]  sdio_run_irqs+0x34/0x60
[   99.973329]  sdio_irq_work+0x1c/0x28
[   99.974930] cros-ec-spi spi2.0: SPI transfer timed out
[   99.976904]  process_one_work+0x210/0x410
[   99.976911]  worker_thread+0x234/0x3dc
[   99.976923]  kthread+0x120/0x130
[   99.982090] cros-ec-spi spi2.0: spi transfer failed: -110
[   99.986054]  ret_from_fork+0x10/0x18
[   99.986063] Code: aa1403e2 2a1503e4 a90023e9 97e37d1a (d4210000)
[   99.986068] ---[ end trace cb6d948c5a0fd6c7 ]---
[  100.017250] Kernel panic - not syncing: Fatal exception
[  100.018879] cros-ec-spi spi2.0: Command xfer error (err:-110)
[  100.023659] SMP: stopping secondary CPUs
[  100.023703] Kernel Offset: 0x251dc00000 from 0xffffff8008000000
[  100.023707] CPU features: 0x0,2188200c
[  100.023709] Memory Limit: none

The simulate fail of sdio is not a real sdio transter fail, it only
set an error status in mmc_should_fail_request after the transfer end,
actually the transfer is success, then sdio_io_rw_ext_helper will
return error status and stop transfer the left data. For example,
the really RX len is 286 bytes, then it will split to 2 blocks in
sdio_io_rw_ext_helper, one is 256 bytes, left is 30 bytes, if the
first 256 bytes get an error status by mmc_should_fail_request,then
the left 30 bytes will not read in this RX operation. Then when the
next RX arrive, the left 30 bytes will be considered as the header
of the read, the top 8 bytes will be considered as ath10k_htc_hdr,
but actually the 8 bytes is not the ath10k_htc_hdr, so the act_len
from this ath10k_htc_hdr is not correct, if it is a big value, such
as 57013, it will trigger skb_panic.

Drop the skb with invalid length will be reasonable.

This patch only effect sdio chips.

Tested with QCA6174 SDIO with firmware WLAN.RMH.4.4.1-00029.

Signed-off-by: Wen Gong <[email protected]>
Signed-off-by: Kalle Valo <[email protected]>
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