============================================ WARNING: possible recursive locking detected 5.9.0-rc3-next-20200903-syzkaller #0 Not tainted -------------------------------------------- syz-executor.5/8808 is trying to acquire lock: ffff888095b48130 (&runtime->sleep){....}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff888095b48130 (&runtime->sleep){....}-{2:2}, at: io_poll_double_wake+0x156/0x510 fs/io_uring.c:4779 but task is already holding lock: ffff88809c276130 (&runtime->sleep){....}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122 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 syz-executor.5/8808: #0: ffff888215368108 (&group->lock){....}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:379 [inline] #0: ffff888215368108 (&group->lock){....}-{2:2}, at: snd_pcm_group_lock_irq sound/core/pcm_native.c:97 [inline] #0: ffff888215368108 (&group->lock){....}-{2:2}, at: snd_pcm_stream_lock_irq sound/core/pcm_native.c:136 [inline] #0: ffff888215368108 (&group->lock){....}-{2:2}, at: snd_pcm_drop+0x131/0x320 sound/core/pcm_native.c:2128 #1: ffff88809c276130 (&runtime->sleep){....}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122 stack backtrace: CPU: 1 PID: 8808 Comm: syz-executor.5 Not tainted 5.9.0-rc3-next-20200903-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:2391 [inline] check_deadlock kernel/locking/lockdep.c:2432 [inline] validate_chain kernel/locking/lockdep.c:3202 [inline] __lock_acquire.cold+0x149/0x398 kernel/locking/lockdep.c:4426 lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 __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+0x156/0x510 fs/io_uring.c:4779 __wake_up_common+0x147/0x650 kernel/sched/wait.c:93 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123 snd_pcm_post_stop+0xe6/0x230 sound/core/pcm_native.c:1434 snd_pcm_action_single sound/core/pcm_native.c:1209 [inline] snd_pcm_action+0x143/0x170 sound/core/pcm_native.c:1290 snd_pcm_stop sound/core/pcm_native.c:1455 [inline] snd_pcm_drop+0x1ab/0x320 sound/core/pcm_native.c:2133 snd_pcm_kernel_ioctl+0x12f/0x240 sound/core/pcm_native.c:3335 snd_pcm_oss_sync+0x230/0x800 sound/core/oss/pcm_oss.c:1711 snd_pcm_oss_ioctl+0x2174/0x3370 sound/core/oss/pcm_oss.c:2590 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl fs/ioctl.c:739 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d5b9 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f4fef20ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000015f80 RCX: 000000000045d5b9 RDX: 0000000000000000 RSI: 0000000000005001 RDI: 0000000000000003 RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c R13: 00007ffe5005004f R14: 00007f4fef20b9c0 R15: 000000000118cf4c