INFO: task syz-executor2:5237 blocked for more than 120 seconds.
      Not tainted 4.4.115-g55a366596 #14
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2   D ffff8800bb0cf8c8 29200  5237   3807 0x00000002
 ffff8800bb0cf8c8 0000000000000000 0000000000000000 0000000000000000
 0000000000000001 ffff8800bb0cf800 ffff8801db31fdb8 ffff8801db31fde0
 ffff8801db31f4d8 ffff8800ba4db000 ffff8800af013000 0000000000000000
Call Trace:
 [<ffffffff837663ba>] schedule+0x7a/0x1b0 kernel/sched/core.c:3353
 [<ffffffff83766bb3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3386
 [<ffffffff8376b176>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8376b176>] mutex_lock_nested+0x306/0x850 kernel/locking/mutex.c:621
 [<ffffffff82d427da>] odev_release+0x4a/0x70 sound/core/seq/oss/seq_oss.c:151
 [<ffffffff81523693>] __fput+0x233/0x6d0 fs/file_table.c:208
 [<ffffffff81523bb5>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8118b9e4>] task_work_run+0x104/0x180 kernel/task_work.c:115
 [<ffffffff81132f8a>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff81132f8a>] do_exit+0x82a/0x2a10 kernel/exit.c:755
 [<ffffffff81139428>] do_group_exit+0x108/0x320 kernel/exit.c:885
 [<ffffffff8115c882>] get_signal+0x4f2/0x1550 kernel/signal.c:2317
 [<ffffffff8100e7fb>] do_signal+0x8b/0x1d40 arch/x86/kernel/signal.c:712
 [<ffffffff810035fa>] exit_to_usermode_loop+0x11a/0x160 arch/x86/entry/common.c:247
 [<ffffffff81006535>] prepare_exit_to_usermode arch/x86/entry/common.c:282 [inline]
 [<ffffffff81006535>] syscall_return_slowpath+0x1b5/0x1f0 arch/x86/entry/common.c:347
 [<ffffffff83774669>] int_ret_from_sys_call+0x25/0xa3
INFO: lockdep is turned off.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 485 Comm: khungtaskd Not tainted 4.4.115-g55a366596 #14
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bac04800 task.stack: ffff8800bb050000
RIP: 0010:[<ffffffff810c3eb7>]  [<ffffffff810c3eb7>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c3eb7>]  [<ffffffff810c3eb7>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c3eb7>]  [<ffffffff810c3eb7>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c3eb7>]  [<ffffffff810c3eb7>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bb057cb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: ffffffff8126a2f2
RDX: 0000000000000c00 RSI: 0000000000000002 RDI: ffffffffff5fb300
RBP: ffff8800bb057ce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: fffffbfff0ad7e2c R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426f3a0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c422c65010 CR3: 00000000b670c000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426f3a0 ffffffff847ef7c0 fffffbfff08fd9ac dffffc0000000000
 ffff8801db31bca0 ffff8800bb057d00 ffffffff810b99eb ffffffff839f6200
 0000000000000003 ffff8800bb057d60 ffffffff81d0ecf4 0000000000000001
Call Trace:
 [<ffffffff810b99eb>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d0ecf4>] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b9a84>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff81368cba>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff81368cba>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81368cba>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81368cba>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff811907e8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83774905>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:506
Code: b3 5f ff f6 c4 10 75 e1 44 89 e8 c1 e0 18 89 04 25 10 b3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 b3 5f ff <41> f7 c4 00 02 00 00 74 1a e8 7b 2f 17 00 4c 89 e7 57 9d 0f 1f 
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.115-g55a366596 #14
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d9b49800 task.stack: ffff8801d9b58000
RIP: 0010:[<ffffffff81d63b06>]  [<ffffffff81d63b06>] check_preemption_disabled+0x6/0x200 lib/smp_processor_id.c:12
RSP: 0018:ffff8801d9b5fc70  EFLAGS: 00000293
RAX: ffff8801d9b49800 RBX: ffffffff83866aa0 RCX: ffffffff81d63d2d
RDX: 0000000000000000 RSI: ffffffff83866aa0 RDI: ffffffff839fe4a0
RBP: ffff8801d9b5fc78 R08: ffff88021fffd058 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffffffff847ebc38 R14: ffffffff83844400 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6c17de2000 CR3: 00000000b670c000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000000 ffff8801d9b5fc90 ffffffff81d63d3c ffffffff847dce48
 ffff8801d9b5fcb8 ffffffff81295f77 0000000000000092 ffffffff847dce48
 0000000000000001 ffff8801d9b5fd40 ffffffff812993cd ffff8801db319c58
Call Trace:
 [<ffffffff81d63d3c>] __this_cpu_preempt_check+0x1c/0x20 lib/smp_processor_id.c:62
 [<ffffffff81295f77>] rcu_sched_qs+0x17/0x180 kernel/rcu/tree.c:251
 [<ffffffff812993cd>] rcu_note_context_switch+0x8d/0x1000 kernel/rcu/tree.c:355
 [<ffffffff8376457d>] __schedule+0x5d/0x1ca0 kernel/sched/core.c:3249
 [<ffffffff837663ba>] schedule+0x7a/0x1b0 kernel/sched/core.c:3353
 [<ffffffff83766bb3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3386
 [<ffffffff81221890>] cpu_idle_loop kernel/sched/idle.c:279 [inline]
 [<ffffffff81221890>] cpu_startup_entry+0x2c0/0x8f0 kernel/sched/idle.c:301
 [<ffffffff810adcb4>] start_secondary+0x304/0x3e0 arch/x86/kernel/smpboot.c:242
Code: 91 ad 79 ff e9 b8 f9 ff ff e8 e7 ad 79 ff e9 ef fa ff ff e8 dd ad 79 ff 48 8b 8d 70 ff ff ff e9 a2 fa ff ff 90 55 48 89 e5 41 57 <41> 56 41 55 49 89 f5 41 54 49 89 fc 53 48 83 ec 08 e8 54 d2 5f