[syzbot] possible deadlock in io_poll_double_wake (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 17e7124a Merge tag '5.12-rc6-smb3' of git://git.samba.org/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=102c3891d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9320464bf47598bd
dashboard link: https://syzkaller.appspot.com/bug?extid=e654d4e15e6b3b9deb53
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15fe3096d00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=147b9431d00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e654d4...@syzkaller.appspotmail.com

============================================
WARNING: possible recursive locking detected
5.12.0-rc6-syzkaller #0 Not tainted
--------------------------------------------
swapper/0/0 is trying to acquire lock:
ffff88802108c130 (&runtime->sleep){..-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline]
ffff88802108c130 (&runtime->sleep){..-.}-{2:2}, at: io_poll_double_wake+0x25f/0x6a0 fs/io_uring.c:4988

but task is already holding lock:
ffff888014fd8130 (&runtime->sleep){..-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:137

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&runtime->sleep);
lock(&runtime->sleep);

*** DEADLOCK ***

May be due to missing lock nesting notation

2 locks held by swapper/0/0:
#0: ffff888020d18108 (&group->lock){..-.}-{2:2}, at: _snd_pcm_stream_lock_irqsave+0x9f/0xd0 sound/core/pcm_native.c:170
#1: ffff888014fd8130 (&runtime->sleep){..-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:137

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
print_deadlock_bug kernel/locking/lockdep.c:2829 [inline]
check_deadlock kernel/locking/lockdep.c:2872 [inline]
validate_chain kernel/locking/lockdep.c:3661 [inline]
__lock_acquire.cold+0x14c/0x3b4 kernel/locking/lockdep.c:4900
lock_acquire kernel/locking/lockdep.c:5510 [inline]
lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5475
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:354 [inline]
io_poll_double_wake+0x25f/0x6a0 fs/io_uring.c:4988
__wake_up_common+0x147/0x650 kernel/sched/wait.c:108
__wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:138
snd_pcm_update_state+0x46a/0x540 sound/core/pcm_lib.c:203
snd_pcm_update_hw_ptr0+0xa75/0x1a50 sound/core/pcm_lib.c:464
snd_pcm_period_elapsed+0x160/0x250 sound/core/pcm_lib.c:1805
dummy_hrtimer_callback+0x94/0x1b0 sound/drivers/dummy.c:377
__run_hrtimer kernel/time/hrtimer.c:1537 [inline]
__hrtimer_run_queues+0x609/0xe40 kernel/time/hrtimer.c:1601
hrtimer_run_softirq+0x17b/0x360 kernel/time/hrtimer.c:1618
__do_softirq+0x29b/0x9f6 kernel/softirq.c:345
invoke_softirq kernel/softirq.c:221 [inline]
__irq_exit_rcu kernel/softirq.c:422 [inline]
irq_exit_rcu+0x134/0x200 kernel/softirq.c:434
sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100
</IRQ>
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:137 [inline]
RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:112 [inline]
RIP: 0010:acpi_idle_do_entry+0x1c9/0x250 drivers/acpi/processor_idle.c:517
Code: cd cb 6e f8 84 db 75 ac e8 14 c5 6e f8 e8 1f b4 74 f8 e9 0c 00 00 00 e8 05 c5 6e f8 0f 00 2d 0e 18 c8 00 e8 f9 c4 6e f8 fb f4 <9c> 5b 81 e3 00 02 00 00 fa 31 ff 48 89 de e8 04 cd 6e f8 48 85 db
RSP: 0018:ffffffff8bc07d60 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffffffff8bcbc400 RSI: ffffffff89052c17 RDI: 0000000000000000
RBP: ffff888015078064 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8179e058 R11: 0000000000000000 R12: 0000000000000001
R13: ffff888015078000 R14: ffff888015078064 R15: ffff888143a48004
acpi_idle_enter+0x361/0x500 drivers/acpi/processor_idle.c:654
cpuidle_enter_state+0x1b1/0xc80 drivers/cpuidle/cpuidle.c:237
cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:351
call_cpuidle kernel/sched/idle.c:158 [inline]
cpuidle_idle_call kernel/sched/idle.c:239 [inline]
do_idle+0x3e1/0x590 kernel/sched/idle.c:300


---
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[Hillf Danton]

On Tue, 13 Apr 2021 14:07:16

Wasnt it fixed by 1c3b3e6527e57, given the same call trace at the first
glance?

[Dmitry Vyukov]

1c3b3e6527e57 is present in the tested tree on 17e7124a. So syzbot
just gave the answer to your question.

[syzbot]

syzbot suspects this issue was fixed by commit:

commit aa43477b040251f451db0d844073ac00a8ab66ee
Author: Pavel Begunkov <asml.s...@gmail.com>
Date: Wed Dec 15 22:08:48 2021 +0000

io_uring: poll rework

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=110d0baa700000
start commit: c9e6606c7fe9 Linux 5.16-rc8
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=4772459294eb89cc
dashboard link: https://syzkaller.appspot.com/bug?extid=e654d4e15e6b3b9deb53
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10f87335b00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15ac8a73b00000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: io_uring: poll rework

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Jens Axboe]

#syz fix: io_uring: poll rework

--
Jens Axboe