INFO: rcu detected stall in snd_pcm_oss_write2

From: syzbot
Date: Fri Apr 06 2018 - 08:04:09 EST

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Hello,

syzbot hit the following crash on upstream commit
e02d37bf55a9a36f22427fd6dd733fe104d817b6 (Thu Apr 5 17:42:07 2018 +0000)
Merge tag 'sound-4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=adc909755650e074e501

So far this crash happened 2 times on upstream.
Unfortunately, I don't have any reproducer for this crash yet.
Raw console output: https://syzkaller.appspot.com/x/log.txt?id=4567980574769152
Kernel config: https://syzkaller.appspot.com/x/.config?id=-4805825610197092128
compiler: gcc (GCC) 8.0.1 20180301 (experimental)

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+adc909755650e074e501@xxxxxxxxxxxxxxxxxxxxxxxxx
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reason=80000021 qualification=0000000000000000
IDTVectoring: info=00000000 errcode=00000000
TSC Offset = 0xfffffd92e6bf78df
TPR Threshold = 0x00
EPT pointer = 0x00000001ab93b01e
INFO: rcu_sched self-detected stall on CPU
0-....: (124999 ticks this GP) idle=81a/1/4611686018427387906 softirq=379270/379270 fqs=31240
(t=125000 jiffies g=195733 c=195732 q=734)
NMI backtrace for cpu 0
CPU: 0 PID: 9961 Comm: syz-executor2 Not tainted 4.16.0+ #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b9/0x29f lib/dump_stack.c:53
nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline]
rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1376
print_cpu_stall kernel/rcu/tree.c:1525 [inline]
check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593
__rcu_pending kernel/rcu/tree.c:3356 [inline]
rcu_pending kernel/rcu/tree.c:3401 [inline]
rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763
update_process_times+0x2d/0x70 kernel/time/timer.c:1636
tick_sched_handle+0xa0/0x180 kernel/time/tick-sched.c:171
tick_sched_timer+0x42/0x130 kernel/time/tick-sched.c:1179
__run_hrtimer kernel/time/hrtimer.c:1337 [inline]
__hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1399
hrtimer_interrupt+0x286/0x650 kernel/time/hrtimer.c:1457
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:862
</IRQ>
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x20 kernel/kcov.c:183
RSP: 0018:ffff88018e3fee20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff85a132bd
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88018e3fee70 R08: ffff88018e044100 R09: 0000000000000006
R10: ffff88018e044100 R11: 0000000000000000 R12: 0000000000000001
R13: ffff8801ceaa2d80 R14: ffff88019269ab00 R15: ffffffffffffffe0
snd_pcm_oss_write2+0x34c/0x460 sound/core/oss/pcm_oss.c:1373
snd_pcm_oss_sync1+0x332/0x5a0 sound/core/oss/pcm_oss.c:1606
snd_pcm_oss_sync.isra.29+0x790/0x980 sound/core/oss/pcm_oss.c:1682
snd_pcm_oss_release+0x214/0x290 sound/core/oss/pcm_oss.c:2559
__fput+0x34d/0x890 fs/file_table.c:209
____fput+0x15/0x20 fs/file_table.c:243
task_work_run+0x1e4/0x290 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x1aee/0x2730 kernel/exit.c:865
do_group_exit+0x16f/0x430 kernel/exit.c:968
get_signal+0x886/0x1960 kernel/signal.c:2469
do_signal+0x90/0x2020 arch/x86/kernel/signal.c:810
exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162
prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
do_syscall_64+0x792/0x9d0 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4552d9
RSP: 002b:00007f0bfca8cce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000072bf80 RCX: 00000000004552d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072bf80
RBP: 000000000072bf80 R08: 0000000000000000 R09: 000000000072bf58
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000a3e81f R14: 00007f0bfca8d9c0 R15: 0000000000000001

---
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Next message: Mika PenttilÃ: "Fwd: regression, imx6 and sgtl5000 sound problems"
Previous message: Michal Hocko: "Re: [PATCH] mm: memcg: make sure memory.events is uptodate when waking pollers"
Next in thread: Dmitry Vyukov: "Re: INFO: rcu detected stall in snd_pcm_oss_write2"
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