INFO: task syz-executor0:5227 blocked for more than 120 seconds.
      Not tainted 4.4.115-gaa856bd #6
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D ffff8800ac2ff648 29256  5227   3860 0x00000002
 ffff8800ac2ff648 0000000000000000 0000000000000000 0000000000000000
 0000000000000001 ffff8800ac2ff600 ffff8801db21fdb8 ffff8801db21fde0
 ffff8801db21f4d8 ffff8800b5f00000 ffff8800aa7c6000 0000000000000000
Call Trace:
 [<ffffffff837662da>] schedule+0x7a/0x1b0 kernel/sched/core.c:3353
 [<ffffffff83766ad3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3386
 [<ffffffff8376b096>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8376b096>] mutex_lock_nested+0x306/0x850 kernel/locking/mutex.c:621
 [<ffffffff82d2ad8d>] snd_seq_do_ioctl+0x15d/0x1b0 sound/core/seq/seq_clientmgr.c:2214
 [<ffffffff82d2aeb7>] snd_seq_kernel_client_ctl+0xd7/0x150 sound/core/seq/seq_clientmgr.c:2432
 [<ffffffff82d54150>] snd_seq_oss_control sound/core/seq/oss/seq_oss_device.h:157 [inline]
 [<ffffffff82d54150>] snd_seq_oss_writeq_clear+0xe0/0x140 sound/core/seq/oss/seq_oss_writeq.c:84
 [<ffffffff82d541cf>] snd_seq_oss_writeq_delete+0x1f/0x30 sound/core/seq/oss/seq_oss_writeq.c:68
 [<ffffffff82d42d71>] free_devinfo+0x61/0xb0 sound/core/seq/oss/seq_oss_init.c:406
 [<ffffffff82d3d015>] port_delete+0xd5/0x110 sound/core/seq/seq_ports.c:273
 [<ffffffff82d3d913>] snd_seq_delete_port+0x1c3/0x200 sound/core/seq/seq_ports.c:303
 [<ffffffff82d29142>] snd_seq_ioctl_delete_port+0xf2/0x1d0 sound/core/seq/seq_clientmgr.c:1326
 [<ffffffff82d2adb2>] snd_seq_do_ioctl+0x182/0x1b0 sound/core/seq/seq_clientmgr.c:2215
 [<ffffffff82d2aeb7>] snd_seq_kernel_client_ctl+0xd7/0x150 sound/core/seq/seq_clientmgr.c:2432
 [<ffffffff82d3bd5f>] snd_seq_event_port_detach+0xaf/0x100 sound/core/seq/seq_ports.c:706
 [<ffffffff82d42e33>] delete_port+0x73/0xb0 sound/core/seq/oss/seq_oss_init.c:354
 [<ffffffff82d43fe4>] snd_seq_oss_release+0xe4/0x130 sound/core/seq/oss/seq_oss_init.c:433
 [<ffffffff82d42782>] odev_release+0x52/0x70 sound/core/seq/oss/seq_oss.c:152
 [<ffffffff815236a3>] __fput+0x233/0x6d0 fs/file_table.c:208
 [<ffffffff81523bc5>] ____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
 [<ffffffff8113965d>] SYSC_exit_group kernel/exit.c:896 [inline]
 [<ffffffff8113965d>] SyS_exit_group+0x1d/0x20 kernel/exit.c:894
 [<ffffffff8377441f>] entry_SYSCALL_64_fastpath+0x1c/0x98
INFO: lockdep is turned off.
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 3633 Comm: rsyslogd Not tainted 4.4.115-gaa856bd #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c7378000 task.stack: ffff8801c6d90000
RIP: 0010:[<ffffffff8123d67e>]  [<ffffffff8123d67e>] lock_acquire+0xe/0x460 kernel/locking/lockdep.c:3581
RSP: 0018:ffff8801c6d97b10  EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffffffff842b79c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff842b79d8
RBP: ffff8801c6d97b10 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 1ffff10038db2f20 R12: 0000000000000282
R13: ffffffff842b79c0 R14: ffff8801c6d97bf0 R15: 0000000000000000
FS:  00007f217b38f700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f18bbbef000 CR3: 00000000ac5ae000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801c6d97b38 ffffffff83773fee ffffffff81220238 ffff8801c6d97be8
 ffff8801c6d97bd0 ffff8801c6d97b70 ffffffff81220238 1ffff10038db2f76
 ffff8801c6d97bd0 0000000000000000 0000000000000fff 0000000000000000
Call Trace:
 [<ffffffff83773fee>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:112 [inline]
 [<ffffffff83773fee>] _raw_spin_lock_irqsave+0x4e/0x70 kernel/locking/spinlock.c:159
 [<ffffffff81220238>] finish_wait+0xa8/0x180 kernel/sched/wait.c:251
 [<ffffffff81268e32>] do_syslog+0x5d2/0xae0 kernel/printk/printk.c:1327
 [<ffffffff8168ef24>] kmsg_read+0x74/0xa0 fs/proc/kmsg.c:39
 [<ffffffff81665d2f>] proc_reg_read+0xef/0x170 fs/proc/inode.c:202
 [<ffffffff8151cfd3>] __vfs_read+0x103/0x440 fs/read_write.c:432
 [<ffffffff8151ee73>] vfs_read+0x123/0x3a0 fs/read_write.c:454
 [<ffffffff815217b9>] SYSC_read fs/read_write.c:569 [inline]
 [<ffffffff815217b9>] SyS_read+0xd9/0x1b0 fs/read_write.c:562
 [<ffffffff8377441f>] entry_SYSCALL_64_fastpath+0x1c/0x98
Code: c0 e9 9f f1 ff ff e8 c2 11 2c 00 e9 73 f1 ff ff 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 <41> 57 45 89 c7 41 56 41 89 ce 41 55 41 89 d5 41 54 41 89 f4 53 
NMI backtrace for cpu 1
CPU: 1 PID: 485 Comm: khungtaskd Not tainted 4.4.115-gaa856bd #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800bacae000 task.stack: ffff8800bacf8000
RIP: 0010:[<ffffffff810c3ec7>]  [<ffffffff810c3ec7>] native_apic_mem_write arch/x86/include/asm/apic.h:94 [inline]
RIP: 0010:[<ffffffff810c3ec7>]  [<ffffffff810c3ec7>] __default_send_IPI_dest_field arch/x86/include/asm/ipi.h:119 [inline]
RIP: 0010:[<ffffffff810c3ec7>]  [<ffffffff810c3ec7>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:61 [inline]
RIP: 0010:[<ffffffff810c3ec7>]  [<ffffffff810c3ec7>] flat_send_IPI_mask+0xf7/0x1a0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800bacffcb8  EFLAGS: 00000046
RAX: 0000000003000000 RBX: 0000000000000c00 RCX: ffffffff8126a292
RDX: 0000000000000c00 RSI: 0000000000000002 RDI: ffffffffff5fb300
RBP: ffff8800bacffce0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: fffffbfff0ad7e2c R12: 0000000000000246
R13: 0000000000000003 R14: ffffffff8426f3a0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c422033840 CR3: 00000000ac5ae000 CR4: 0000000000160670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8426f3a0 ffffffff847ef7c0 fffffbfff08fd9ac dffffc0000000000
 ffff8801db31bca0 ffff8800bacffd00 ffffffff810b99fb ffffffff839f61c0
 0000000000000003 ffff8800bacffd60 ffffffff81d0ed14 0000000000000001
Call Trace:
 [<ffffffff810b99fb>] nmi_raise_cpu_backtrace+0x5b/0x70 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81d0ed14>] nmi_trigger_all_cpu_backtrace+0x4a4/0x550 lib/nmi_backtrace.c:85
 [<ffffffff810b9a94>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff81368cca>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff81368cca>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81368cca>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81368cca>] watchdog+0x6fa/0xae0 kernel/hung_task.c:238
 [<ffffffff811907e8>] kthread+0x268/0x300 kernel/kthread.c:211
 [<ffffffff83774845>] 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 0b 2f 17 00 4c 89 e7 57 9d 0f 1f