gen7 tracking specific_ctx_id #25

rib · 2016-10-07T17:24:49Z

Currently on gen7 specific_ctx_id is only updated via i915_oa_legacy_context_pin_notify which implies we won't have a valid id if the context was pinned before opening up an i915-perf stream, unless there is some need to re-pin the context while the stream is open.

Also i915-perf currently depends on zero being an invalid ctx offset which is probably ok, but strictly speaking a ctx could be mapped at zero.

The text was updated successfully, but these errors were encountered:

As Eric Dumazet pointed out this also needs to be fixed in IPv6. v2: Contains the IPv6 tcp/Ipv6 dccp patches as well. We have seen a few incidents lately where a dst_enty has been freed with a dangling TCP socket reference (sk->sk_dst_cache) pointing to that dst_entry. If the conditions/timings are right a crash then ensues when the freed dst_entry is referenced later on. A Common crashing back trace is: #8 [] page_fault at ffffffff8163e648 [exception RIP: __tcp_ack_snd_check+74] . . #9 [] tcp_rcv_established at ffffffff81580b64 #10 [] tcp_v4_do_rcv at ffffffff8158b54a #11 [] tcp_v4_rcv at ffffffff8158cd02 #12 [] ip_local_deliver_finish at ffffffff815668f4 #13 [] ip_local_deliver at ffffffff81566bd9 #14 [] ip_rcv_finish at ffffffff8156656d #15 [] ip_rcv at ffffffff81566f06 #16 [] __netif_receive_skb_core at ffffffff8152b3a2 #17 [] __netif_receive_skb at ffffffff8152b608 #18 [] netif_receive_skb at ffffffff8152b690 #19 [] vmxnet3_rq_rx_complete at ffffffffa015eeaf [vmxnet3] #20 [] vmxnet3_poll_rx_only at ffffffffa015f32a [vmxnet3] #21 [] net_rx_action at ffffffff8152bac2 #22 [] __do_softirq at ffffffff81084b4f #23 [] call_softirq at ffffffff8164845c #24 [] do_softirq at ffffffff81016fc5 #25 [] irq_exit at ffffffff81084ee5 torvalds#26 [] do_IRQ at ffffffff81648ff8 Of course it may happen with other NIC drivers as well. It's found the freed dst_entry here: 224 static bool tcp_in_quickack_mode(struct sock *sk)↩ 225 {↩ 226 ▹ const struct inet_connection_sock *icsk = inet_csk(sk);↩ 227 ▹ const struct dst_entry *dst = __sk_dst_get(sk);↩ 228 ↩ 229 ▹ return (dst && dst_metric(dst, RTAX_QUICKACK)) ||↩ 230 ▹ ▹ (icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);↩ 231 }↩ But there are other backtraces attributed to the same freed dst_entry in netfilter code as well. All the vmcores showed 2 significant clues: - Remote hosts behind the default gateway had always been redirected to a different gateway. A rtable/dst_entry will be added for that host. Making more dst_entrys with lower reference counts. Making this more probable. - All vmcores showed a postitive LockDroppedIcmps value, e.g: LockDroppedIcmps 267 A closer look at the tcp_v4_err() handler revealed that do_redirect() will run regardless of whether user space has the socket locked. This can result in a race condition where the same dst_entry cached in sk->sk_dst_entry can be decremented twice for the same socket via: do_redirect()->__sk_dst_check()-> dst_release(). Which leads to the dst_entry being prematurely freed with another socket pointing to it via sk->sk_dst_cache and a subsequent crash. To fix this skip do_redirect() if usespace has the socket locked. Instead let the redirect take place later when user space does not have the socket locked. The dccp/IPv6 code is very similar in this respect, so fixing it there too. As Eric Garver pointed out the following commit now invalidates routes. Which can set the dst->obsolete flag so that ipv4_dst_check() returns null and triggers the dst_release(). Fixes: ceb3320 ("ipv4: Kill routes during PMTU/redirect updates.") Cc: Eric Garver <[email protected]> Cc: Hannes Sowa <[email protected]> Signed-off-by: Jon Maxwell <[email protected]> Signed-off-by: David S. Miller <[email protected]>

commit 1c7de2b upstream. There is at least one Chelsio 10Gb card which uses VPD area to store some non-standard blocks (example below). However pci_vpd_size() returns the length of the first block only assuming that there can be only one VPD "End Tag". Since 4e1a635 ("vfio/pci: Use kernel VPD access functions"), VFIO blocks access beyond that offset, which prevents the guest "cxgb3" driver from probing the device. The host system does not have this problem as its driver accesses the config space directly without pci_read_vpd(). Add a quirk to override the VPD size to a bigger value. The maximum size is taken from EEPROMSIZE in drivers/net/ethernet/chelsio/cxgb3/common.h. We do not read the tag as the cxgb3 driver does as the driver supports writing to EEPROM/VPD and when it writes, it only checks for 8192 bytes boundary. The quirk is registered for all devices supported by the cxgb3 driver. This adds a quirk to the PCI layer (not to the cxgb3 driver) as the cxgb3 driver itself accesses VPD directly and the problem only exists with the vfio-pci driver (when cxgb3 is not running on the host and may not be even loaded) which blocks accesses beyond the first block of VPD data. However vfio-pci itself does not have quirks mechanism so we add it to PCI. This is the controller: Ethernet controller [0200]: Chelsio Communications Inc T310 10GbE Single Port Adapter [1425:0030] This is what I parsed from its VPD: === b'\x82*\x0010 Gigabit Ethernet-SR PCI Express Adapter\x90J\x00EC\x07D76809 FN\x0746K' 0000 Large item 42 bytes; name 0x2 Identifier String b'10 Gigabit Ethernet-SR PCI Express Adapter' 002d Large item 74 bytes; name 0x10 #00 [EC] len=7: b'D76809 ' #0a [FN] len=7: b'46K7897' rib#14 [PN] len=7: b'46K7897' #1e [MN] len=4: b'1037' rib#25 [FC] len=4: b'5769' #2c [SN] len=12: b'YL102035603V' #3b [NA] len=12: b'00145E992ED1' 007a Small item 1 bytes; name 0xf End Tag 0c00 Large item 16 bytes; name 0x2 Identifier String b'S310E-SR-X ' 0c13 Large item 234 bytes; name 0x10 #00 [PN] len=16: b'TBD ' rib#13 [EC] len=16: b'110107730D2 ' torvalds#26 [SN] len=16: b'97YL102035603V ' torvalds#39 [NA] len=12: b'00145E992ED1' torvalds#48 [V0] len=6: b'175000' torvalds#51 [V1] len=6: b'266666' #5a [V2] len=6: b'266666' torvalds#63 [V3] len=6: b'2000 ' #6c [V4] len=2: b'1 ' torvalds#71 [V5] len=6: b'c2 ' #7a [V6] len=6: b'0 ' torvalds#83 [V7] len=2: b'1 ' torvalds#88 [V8] len=2: b'0 ' #8d [V9] len=2: b'0 ' torvalds#92 [VA] len=2: b'0 ' torvalds#97 [RV] len=80: b's\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'... 0d00 Large item 252 bytes; name 0x11 #00 [VC] len=16: b'122310_1222 dp ' rib#13 [VD] len=16: b'610-0001-00 H1\x00\x00' torvalds#26 [VE] len=16: b'122310_1353 fp ' torvalds#39 [VF] len=16: b'610-0001-00 H1\x00\x00' #4c [RW] len=173: b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'... 0dff Small item 0 bytes; name 0xf End Tag 10f3 Large item 13315 bytes; name 0x62 !!! unknown item name 98: b'\xd0\x03\x00@`\x0c\x08\x00\x00\x00\x00\x00\x00\x00\x00\x00' === Signed-off-by: Alexey Kardashevskiy <[email protected]> Signed-off-by: Bjorn Helgaas <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

[ Upstream commit 45caeaa ] As Eric Dumazet pointed out this also needs to be fixed in IPv6. v2: Contains the IPv6 tcp/Ipv6 dccp patches as well. We have seen a few incidents lately where a dst_enty has been freed with a dangling TCP socket reference (sk->sk_dst_cache) pointing to that dst_entry. If the conditions/timings are right a crash then ensues when the freed dst_entry is referenced later on. A Common crashing back trace is: rib#8 [] page_fault at ffffffff8163e648 [exception RIP: __tcp_ack_snd_check+74] . . rib#9 [] tcp_rcv_established at ffffffff81580b64 rib#10 [] tcp_v4_do_rcv at ffffffff8158b54a rib#11 [] tcp_v4_rcv at ffffffff8158cd02 rib#12 [] ip_local_deliver_finish at ffffffff815668f4 rib#13 [] ip_local_deliver at ffffffff81566bd9 rib#14 [] ip_rcv_finish at ffffffff8156656d rib#15 [] ip_rcv at ffffffff81566f06 rib#16 [] __netif_receive_skb_core at ffffffff8152b3a2 rib#17 [] __netif_receive_skb at ffffffff8152b608 rib#18 [] netif_receive_skb at ffffffff8152b690 rib#19 [] vmxnet3_rq_rx_complete at ffffffffa015eeaf [vmxnet3] rib#20 [] vmxnet3_poll_rx_only at ffffffffa015f32a [vmxnet3] rib#21 [] net_rx_action at ffffffff8152bac2 rib#22 [] __do_softirq at ffffffff81084b4f rib#23 [] call_softirq at ffffffff8164845c rib#24 [] do_softirq at ffffffff81016fc5 rib#25 [] irq_exit at ffffffff81084ee5 torvalds#26 [] do_IRQ at ffffffff81648ff8 Of course it may happen with other NIC drivers as well. It's found the freed dst_entry here: 224 static bool tcp_in_quickack_mode(struct sock *sk)↩ 225 {↩ 226 ▹ const struct inet_connection_sock *icsk = inet_csk(sk);↩ 227 ▹ const struct dst_entry *dst = __sk_dst_get(sk);↩ 228 ↩ 229 ▹ return (dst && dst_metric(dst, RTAX_QUICKACK)) ||↩ 230 ▹ ▹ (icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);↩ 231 }↩ But there are other backtraces attributed to the same freed dst_entry in netfilter code as well. All the vmcores showed 2 significant clues: - Remote hosts behind the default gateway had always been redirected to a different gateway. A rtable/dst_entry will be added for that host. Making more dst_entrys with lower reference counts. Making this more probable. - All vmcores showed a postitive LockDroppedIcmps value, e.g: LockDroppedIcmps 267 A closer look at the tcp_v4_err() handler revealed that do_redirect() will run regardless of whether user space has the socket locked. This can result in a race condition where the same dst_entry cached in sk->sk_dst_entry can be decremented twice for the same socket via: do_redirect()->__sk_dst_check()-> dst_release(). Which leads to the dst_entry being prematurely freed with another socket pointing to it via sk->sk_dst_cache and a subsequent crash. To fix this skip do_redirect() if usespace has the socket locked. Instead let the redirect take place later when user space does not have the socket locked. The dccp/IPv6 code is very similar in this respect, so fixing it there too. As Eric Garver pointed out the following commit now invalidates routes. Which can set the dst->obsolete flag so that ipv4_dst_check() returns null and triggers the dst_release(). Fixes: ceb3320 ("ipv4: Kill routes during PMTU/redirect updates.") Cc: Eric Garver <[email protected]> Cc: Hannes Sowa <[email protected]> Signed-off-by: Jon Maxwell <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>

Commit 4f350c6 (kvm: nVMX: Handle deferred early VMLAUNCH/VMRESUME failure properly) can result in L1(run kvm-unit-tests/run_tests.sh vmx_controls in L1) null pointer deference and also L0 calltrace when EPT=0 on both L0 and L1. In L1: BUG: unable to handle kernel paging request at ffffffffc015bf8f IP: vmx_vcpu_run+0x202/0x510 [kvm_intel] PGD 146e13067 P4D 146e13067 PUD 146e15067 PMD 3d2686067 PTE 3d4af9161 Oops: 0003 [rib#1] PREEMPT SMP CPU: 2 PID: 1798 Comm: qemu-system-x86 Not tainted 4.14.0-rc4+ rib#6 RIP: 0010:vmx_vcpu_run+0x202/0x510 [kvm_intel] Call Trace: WARNING: kernel stack frame pointer at ffffb86f4988bc18 in qemu-system-x86:1798 has bad value 0000000000000002 In L0: -----------[ cut here ]------------ WARNING: CPU: 6 PID: 4460 at /home/kernel/linux/arch/x86/kvm//vmx.c:9845 vmx_inject_page_fault_nested+0x130/0x140 [kvm_intel] CPU: 6 PID: 4460 Comm: qemu-system-x86 Tainted: G OE 4.14.0-rc7+ rib#25 RIP: 0010:vmx_inject_page_fault_nested+0x130/0x140 [kvm_intel] Call Trace: paging64_page_fault+0x500/0xde0 [kvm] ? paging32_gva_to_gpa_nested+0x120/0x120 [kvm] ? nonpaging_page_fault+0x3b0/0x3b0 [kvm] ? __asan_storeN+0x12/0x20 ? paging64_gva_to_gpa+0xb0/0x120 [kvm] ? paging64_walk_addr_generic+0x11a0/0x11a0 [kvm] ? lock_acquire+0x2c0/0x2c0 ? vmx_read_guest_seg_ar+0x97/0x100 [kvm_intel] ? vmx_get_segment+0x2a6/0x310 [kvm_intel] ? sched_clock+0x1f/0x30 ? check_chain_key+0x137/0x1e0 ? __lock_acquire+0x83c/0x2420 ? kvm_multiple_exception+0xf2/0x220 [kvm] ? debug_check_no_locks_freed+0x240/0x240 ? debug_smp_processor_id+0x17/0x20 ? __lock_is_held+0x9e/0x100 kvm_mmu_page_fault+0x90/0x180 [kvm] kvm_handle_page_fault+0x15c/0x310 [kvm] ? __lock_is_held+0x9e/0x100 handle_exception+0x3c7/0x4d0 [kvm_intel] vmx_handle_exit+0x103/0x1010 [kvm_intel] ? kvm_arch_vcpu_ioctl_run+0x1628/0x2e20 [kvm] The commit avoids to load host state of vmcs12 as vmcs01's guest state since vmcs12 is not modified (except for the VM-instruction error field) if the checking of vmcs control area fails. However, the mmu context is switched to nested mmu in prepare_vmcs02() and it will not be reloaded since load_vmcs12_host_state() is skipped when nested VMLAUNCH/VMRESUME fails. This patch fixes it by reloading mmu context when nested VMLAUNCH/VMRESUME fails. Reviewed-by: Jim Mattson <[email protected]> Reviewed-by: Krish Sadhukhan <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Radim Krčmář <[email protected]> Cc: Jim Mattson <[email protected]> Signed-off-by: Wanpeng Li <[email protected]> Reviewed-by: Paolo Bonzini <[email protected]> Signed-off-by: Radim Krčmář <[email protected]>

Because the HMAC template didn't check that its underlying hash algorithm is unkeyed, trying to use "hmac(hmac(sha3-512-generic))" through AF_ALG or through KEYCTL_DH_COMPUTE resulted in the inner HMAC being used without having been keyed, resulting in sha3_update() being called without sha3_init(), causing a stack buffer overflow. This is a very old bug, but it seems to have only started causing real problems when SHA-3 support was added (requires CONFIG_CRYPTO_SHA3) because the innermost hash's state is ->import()ed from a zeroed buffer, and it just so happens that other hash algorithms are fine with that, but SHA-3 is not. However, there could be arch or hardware-dependent hash algorithms also affected; I couldn't test everything. Fix the bug by introducing a function crypto_shash_alg_has_setkey() which tests whether a shash algorithm is keyed. Then update the HMAC template to require that its underlying hash algorithm is unkeyed. Here is a reproducer: #include <linux/if_alg.h> #include <sys/socket.h> int main() { int algfd; struct sockaddr_alg addr = { .salg_type = "hash", .salg_name = "hmac(hmac(sha3-512-generic))", }; char key[4096] = { 0 }; algfd = socket(AF_ALG, SOCK_SEQPACKET, 0); bind(algfd, (const struct sockaddr *)&addr, sizeof(addr)); setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key)); } Here was the KASAN report from syzbot: BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:341 [inline] BUG: KASAN: stack-out-of-bounds in sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 Write of size 4096 at addr ffff8801cca07c40 by task syzkaller076574/3044 CPU: 1 PID: 3044 Comm: syzkaller076574 Not tainted 4.14.0-mm1+ rib#25 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x25b/0x340 mm/kasan/report.c:409 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x137/0x190 mm/kasan/kasan.c:267 memcpy+0x37/0x50 mm/kasan/kasan.c:303 memcpy include/linux/string.h:341 [inline] sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161 crypto_shash_update+0xcb/0x220 crypto/shash.c:109 shash_finup_unaligned+0x2a/0x60 crypto/shash.c:151 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 hmac_finup+0x182/0x330 crypto/hmac.c:152 crypto_shash_finup+0xc4/0x120 crypto/shash.c:165 shash_digest_unaligned+0x9e/0xd0 crypto/shash.c:172 crypto_shash_digest+0xc4/0x120 crypto/shash.c:186 hmac_setkey+0x36a/0x690 crypto/hmac.c:66 crypto_shash_setkey+0xad/0x190 crypto/shash.c:64 shash_async_setkey+0x47/0x60 crypto/shash.c:207 crypto_ahash_setkey+0xaf/0x180 crypto/ahash.c:200 hash_setkey+0x40/0x90 crypto/algif_hash.c:446 alg_setkey crypto/af_alg.c:221 [inline] alg_setsockopt+0x2a1/0x350 crypto/af_alg.c:254 SYSC_setsockopt net/socket.c:1851 [inline] SyS_setsockopt+0x189/0x360 net/socket.c:1830 entry_SYSCALL_64_fastpath+0x1f/0x96 Reported-by: syzbot <[email protected]> Cc: <[email protected]> Signed-off-by: Eric Biggers <[email protected]> Signed-off-by: Herbert Xu <[email protected]>

Add missing prepare/unprepare operations for fbi->clk, this fixes following kernel warning: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:874 clk_core_enable+0x2c/0x1b0 Enabling unprepared disp0_clk Modules linked in: CPU: 0 PID: 1 Comm: swapper Not tainted 4.18.0-rc8-00032-g02b43ddd4f21-dirty rib#25 Hardware name: Marvell MMP2 (Device Tree Support) [<c010f7cc>] (unwind_backtrace) from [<c010cc6c>] (show_stack+0x10/0x14) [<c010cc6c>] (show_stack) from [<c011dab4>] (__warn+0xd8/0xf0) [<c011dab4>] (__warn) from [<c011db10>] (warn_slowpath_fmt+0x44/0x6c) [<c011db10>] (warn_slowpath_fmt) from [<c043898c>] (clk_core_enable+0x2c/0x1b0) [<c043898c>] (clk_core_enable) from [<c0439ec8>] (clk_core_enable_lock+0x18/0x2c) [<c0439ec8>] (clk_core_enable_lock) from [<c0436698>] (pxa168fb_probe+0x464/0x6ac) [<c0436698>] (pxa168fb_probe) from [<c04779a0>] (platform_drv_probe+0x48/0x94) [<c04779a0>] (platform_drv_probe) from [<c0475bec>] (driver_probe_device+0x328/0x470) [<c0475bec>] (driver_probe_device) from [<c0475de4>] (__driver_attach+0xb0/0x124) [<c0475de4>] (__driver_attach) from [<c0473c38>] (bus_for_each_dev+0x64/0xa0) [<c0473c38>] (bus_for_each_dev) from [<c0474ee0>] (bus_add_driver+0x1b8/0x230) [<c0474ee0>] (bus_add_driver) from [<c0476a20>] (driver_register+0xac/0xf0) [<c0476a20>] (driver_register) from [<c0102dd4>] (do_one_initcall+0xb8/0x1f0) [<c0102dd4>] (do_one_initcall) from [<c0b010a0>] (kernel_init_freeable+0x294/0x2e0) [<c0b010a0>] (kernel_init_freeable) from [<c07e9eb8>] (kernel_init+0x8/0x10c) [<c07e9eb8>] (kernel_init) from [<c01010e8>] (ret_from_fork+0x14/0x2c) Exception stack(0xd008bfb0 to 0xd008bff8) bfa0: 00000000 00000000 00000000 00000000 bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 ---[ end trace c0af40f9e2ed7cb4 ]--- Signed-off-by: Lubomir Rintel <[email protected]> [b.zolnierkie: enhance patch description a bit] Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>

…ives while handle_mm_fault do_page_fault() forgot to relinquish mmap_sem if a signal came while handling handle_mm_fault() - due to say a ctl+c or oom etc. This would later cause a deadlock by acquiring it twice. This came to light when running libc testsuite tst-tls3-malloc test but is likely also the cause for prior seen LTP failures. Using lockdep clearly showed what the issue was. | # while true; do ./tst-tls3-malloc ; done | Didn't expect signal from child: got `Segmentation fault' | ^C | ============================================ | WARNING: possible recursive locking detected | 4.17.0+ rib#25 Not tainted | -------------------------------------------- | tst-tls3-malloc/510 is trying to acquire lock: | 606c7728 (&mm->mmap_sem){++++}, at: __might_fault+0x28/0x5c | |but task is already holding lock: |606c7728 (&mm->mmap_sem){++++}, at: do_page_fault+0x9c/0x2a0 | | other info that might help us debug this: | Possible unsafe locking scenario: | | CPU0 | ---- | lock(&mm->mmap_sem); | lock(&mm->mmap_sem); | | *** DEADLOCK *** | ------------------------------------------------------------ What the change does is not obvious (note to myself) prior code was | do_page_fault | | down_read() <-- lock taken | handle_mm_fault <-- signal pending as this runs | if fatal_signal_pending | if VM_FAULT_ERROR | up_read | if user_mode | return <-- lock still held, this was the BUG New code | do_page_fault | | down_read() <-- lock taken | handle_mm_fault <-- signal pending as this runs | if fatal_signal_pending | if VM_FAULT_RETRY | return <-- not same case as above, but still OK since | core mm already relinq lock for FAULT_RETRY | ... | | < Now falls through for bug case above > | | up_read() <-- lock relinquished Cc: [email protected] Signed-off-by: Vineet Gupta <[email protected]>

Eric Biggers reported: > The following commit, which went into v4.20, introduced undefined behavior when > sys_rt_sigqueueinfo() is called with sig=0: > > commit 4ce5f9c > Author: Eric W. Biederman <[email protected]> > Date: Tue Sep 25 12:59:31 2018 +0200 > > signal: Use a smaller struct siginfo in the kernel > > In sig_specific_sicodes(), used from known_siginfo_layout(), the expression > '1ULL << ((sig)-1)' is undefined as it evaluates to 1ULL << 4294967295. > > Reproducer: > > #include <signal.h> > #include <sys/syscall.h> > #include <unistd.h> > > int main(void) > { > siginfo_t si = { .si_code = 1 }; > syscall(__NR_rt_sigqueueinfo, 0, 0, &si); > } > > UBSAN report for v5.0-rc1: > > UBSAN: Undefined behaviour in kernel/signal.c:2946:7 > shift exponent 4294967295 is too large for 64-bit type 'long unsigned int' > CPU: 2 PID: 346 Comm: syz_signal Not tainted 5.0.0-rc1 rib#25 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x70/0xa5 lib/dump_stack.c:113 > ubsan_epilogue+0xd/0x40 lib/ubsan.c:159 > __ubsan_handle_shift_out_of_bounds+0x12c/0x170 lib/ubsan.c:425 > known_siginfo_layout+0xae/0xe0 kernel/signal.c:2946 > post_copy_siginfo_from_user kernel/signal.c:3009 [inline] > __copy_siginfo_from_user+0x35/0x60 kernel/signal.c:3035 > __do_sys_rt_sigqueueinfo kernel/signal.c:3553 [inline] > __se_sys_rt_sigqueueinfo kernel/signal.c:3549 [inline] > __x64_sys_rt_sigqueueinfo+0x31/0x70 kernel/signal.c:3549 > do_syscall_64+0x4c/0x1b0 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x433639 > Code: c4 18 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b 27 00 00 c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007fffcb289fc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000081 > RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000433639 > RDX: 00007fffcb289fd0 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 00000000006b2018 R08: 000000000000004d R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401560 > R13: 00000000004015f0 R14: 0000000000000000 R15: 0000000000000000 I have looked at the other callers of siginmask and they all appear to in locations where sig can not be zero. I have looked at the code generation of adding an extra test against zero and gcc was able with a simple decrement instruction to combine the two tests together. So the at most adding this test cost a single cpu cycle. In practice that decrement instruction was already present as part of the mask comparison, so the only change was when the instruction was executed. So given that it is cheap, and obviously correct to update siginmask to verify the signal is not zero. Fix this issue there to avoid any future problems. Reported-by: Eric Biggers <[email protected]> Fixes: 4ce5f9c ("signal: Use a smaller struct siginfo in the kernel") Signed-off-by: "Eric W. Biederman" <[email protected]>

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gen7 tracking specific_ctx_id #25

gen7 tracking specific_ctx_id #25

rib commented Oct 7, 2016

gen7 tracking specific_ctx_id #25

gen7 tracking specific_ctx_id #25

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rib commented Oct 7, 2016