INFO: task syz-executor4:2373 blocked for more than 120 seconds.
      Not tainted 4.9.46-g9100442 #38
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D28824  2373      1 0x00000002
 ffff8801d14eb000 ffff8801c9b95a40 ffff8801cd59c000 ffff8801d5c5c800
 ffff8801db321518 ffff8801d5c57568 ffffffff8389961b 0000000000000246
 ffff8801d14eb000 0000000000000000 ffff8801db321e40 ffff8801db321e68
Call Trace:
 [<ffffffff8389abd2>] schedule+0x92/0x1b0 kernel/sched/core.c:3625
 [<ffffffff8389b543>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3658
 [<ffffffff838a0b52>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff838a0b52>] mutex_lock_nested+0x312/0x870 kernel/locking/mutex.c:621
 [<ffffffff82d9ed9a>] snd_timer_close+0x3a/0x670 sound/core/timer.c:333
 [<ffffffff82e17993>] snd_seq_timer_close+0x93/0xb0 sound/core/seq/seq_timer.c:326
 [<ffffffff82e108ae>] queue_delete+0x4e/0xb0 sound/core/seq/seq_queue.c:147
 [<ffffffff82e117cc>] snd_seq_queue_delete+0x3c/0x50 sound/core/seq/seq_queue.c:219
 [<ffffffff82e05a9a>] snd_seq_ioctl_delete_queue+0x6a/0x90 sound/core/seq/seq_clientmgr.c:1529
 [<ffffffff82e034a2>] snd_seq_kernel_client_ctl+0x122/0x160 sound/core/seq/seq_clientmgr.c:2345
 [<ffffffff82e20322>] delete_seq_queue.part.3+0xa2/0x110 sound/core/seq/oss/seq_oss_init.c:389
 [<ffffffff82e20feb>] delete_seq_queue sound/core/seq/oss/seq_oss_init.c:385 [inline]
 [<ffffffff82e20feb>] snd_seq_oss_release+0xfb/0x130 sound/core/seq/oss/seq_oss_init.c:434
 [<ffffffff82e1f702>] odev_release+0x52/0x70 sound/core/seq/oss/seq_oss.c:153
 [<ffffffff815740ac>] __fput+0x28c/0x6e0 fs/file_table.c:208
 [<ffffffff81574585>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff81195d75>] task_work_run+0x115/0x190 kernel/task_work.c:116
 [<ffffffff8113d02e>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff8113d02e>] do_exit+0x82e/0x2a50 kernel/exit.c:833
 [<ffffffff81143718>] do_group_exit+0x108/0x320 kernel/exit.c:937
 [<ffffffff811663bc>] get_signal+0x55c/0x1600 kernel/signal.c:2315
 [<ffffffff81052b97>] do_signal+0x87/0x1960 arch/x86/kernel/signal.c:807
 [<ffffffff81003a35>] exit_to_usermode_loop+0xe5/0x130 arch/x86/entry/common.c:156
 [<ffffffff81006350>] prepare_exit_to_usermode arch/x86/entry/common.c:190 [inline]
 [<ffffffff81006350>] syscall_return_slowpath+0x1a0/0x1e0 arch/x86/entry/common.c:259
 [<ffffffff838aae26>] entry_SYSCALL_64_fastpath+0xc4/0xc6
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 PID: 514 Comm: khungtaskd Not tainted 4.9.46-g9100442 #38
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8f8fd00 ffffffff81d93129 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810bd020 ffff8801d8f8fd38
 ffffffff81d9e23d 0000000000000000 0000000000000000 ffff8801cc643418
Call Trace:
 [<ffffffff81d93129>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d93129>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9e23d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9e377>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810bd114>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81372900>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81372900>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81372900>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81372900>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119acdd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838ab02a>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2382 Comm: syz-executor2 Not tainted 4.9.46-g9100442 #38
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d0d48000 task.stack: ffff8801cb1a0000
RIP: 0010:[<ffffffff81dc116a>] 
c [<ffffffff81dc116a>] rdtsc_ordered arch/x86/lib/delay.c:78 [inline]
RIP: 0010:[<ffffffff81dc116a>] 
c [<ffffffff81dc116a>] delay_tsc+0x4a/0xc0 arch/x86/lib/delay.c:60
RSP: 0018:ffff8801cb1a7868  EFLAGS: 00000246
RAX: 0000000000000001 RBX: 000002928b6745dd RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff83c17340 RDI: ffffffff83c17380
RBP: ffff8801cb1a7888 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 1ffff10039634ede R12: 000002928b671cfc
R13: 00000000000059d9 R14: 0000000000000001 R15: ffffffff82d9f3d0
FS:  00007f3b6c419700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd1bf9fd000 CR3: 00000001d0fb1000 CR4: 00000000001406e0
Stack:
 ffffed00390a3742
c ffff8801c851ba00
c ffff8801c851ba00
c ffff8801d12da8b0
c
 ffff8801cb1a7898
c ffffffff81dc10ab
c ffff8801cb1a78f0
c ffffffff82d9ee57
c
 ffff8801c851ba10
c ffff8801c6da1010
c ffff8801d12da8b0
c ffff8801d12da780
c
Call Trace:
 [<ffffffff81dc10ab>] __delay arch/x86/lib/delay.c:153 [inline]
 [<ffffffff81dc10ab>] __const_udelay+0x2b/0x30 arch/x86/lib/delay.c:167
 [<ffffffff82d9ee57>] snd_timer_close+0xf7/0x670 sound/core/timer.c:345
 [<ffffffff82d9f467>] snd_timer_user_release+0x97/0x130 sound/core/timer.c:1365
 [<ffffffff815740ac>] __fput+0x28c/0x6e0 fs/file_table.c:208
 [<ffffffff81574585>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff81195d75>] task_work_run+0x115/0x190 kernel/task_work.c:116
 [<ffffffff8113d02e>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff8113d02e>] do_exit+0x82e/0x2a50 kernel/exit.c:833
 [<ffffffff81143718>] do_group_exit+0x108/0x320 kernel/exit.c:937
 [<ffffffff811663bc>] get_signal+0x55c/0x1600 kernel/signal.c:2315
 [<ffffffff81052b97>] do_signal+0x87/0x1960 arch/x86/kernel/signal.c:807
 [<ffffffff81003a35>] exit_to_usermode_loop+0xe5/0x130 arch/x86/entry/common.c:156
 [<ffffffff81006350>] prepare_exit_to_usermode arch/x86/entry/common.c:190 [inline]
 [<ffffffff81006350>] syscall_return_slowpath+0x1a0/0x1e0 arch/x86/entry/common.c:259
 [<ffffffff838aae26>] entry_SYSCALL_64_fastpath+0xc4/0xc6
Code: 
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c