INFO: task syz-executor.1:3434 blocked for more than 140 seconds.
      Not tainted 4.9.141+ #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D29816  3434   3432 0x20020000
 ffff8801d06fdf00 0000000000000000 ffff8801d2f4f380 ffff8801da6b2f80
 ffff8801db721018 ffff8801d13b7b80 ffffffff828075c2 ffffffff8432c608
 ffffffff83cc61c0 ffff8801d06fe7d8 00000000000031cb ffff8801db7218f0
Call Trace:
 [<ffffffff82808aef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff828142d5>] schedule_timeout+0x735/0xe20 kernel/time/timer.c:1771
 [<ffffffff8280a63f>] do_wait_for_common kernel/sched/completion.c:75 [inline]
 [<ffffffff8280a63f>] __wait_for_common kernel/sched/completion.c:93 [inline]
 [<ffffffff8280a63f>] wait_for_common+0x3ef/0x5d0 kernel/sched/completion.c:101
 [<ffffffff8280a838>] wait_for_completion+0x18/0x20 kernel/sched/completion.c:122
 [<ffffffff815ff490>] SYSC_io_destroy fs/aio.c:1414 [inline]
 [<ffffffff815ff490>] SyS_io_destroy+0x2c0/0x340 fs/aio.c:1392
 [<ffffffff81006311>] do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline]
 [<ffffffff81006311>] do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390
 [<ffffffff82818de0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131c0cc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff813fe63f>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2020:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d37362>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor.4/2297:
 #0:  (tasklist_lock){.+.+..}, at: [<ffffffff810e5158>] release_task.part.4+0x148/0x14b0 kernel/exit.c:183

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.141+ #23
 ffff8801d9907d08 ffffffff81b42e79 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810983b0 ffff8801d9907d40
 ffffffff81b4df89 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b42e79>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b42e79>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b4df89>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b4df1c>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff810984b4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c65d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c65d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c65d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c65d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff81142c3d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff82817a5c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2298 Comm: syz-executor.5 Not tainted 4.9.141+ #23
task: ffff8801c7815f00 task.stack: ffff8801cae48000
RIP: 0010:[<ffffffff810e9249>] 
c [<ffffffff810e9249>] wait_consider_task+0x2f9/0x3620 kernel/exit.c:1401
RSP: 0018:ffff8801cae4fa30  EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8801c5c64768 RCX: 0000000000000000
RDX: 1ffff10038b8c8ed RSI: ffffffff810e9220 RDI: 0000000000000246
RBP: ffff8801cae4fb88 R08: ffffed00395c9f1f R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8801c5c64740 R14: ffff8801cae4fc9c R15: ffff8801cae4fc98
FS:  0000000000000000(0000) GS:ffff8801db600000(0063) knlGS:000000000a363900
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00007fba78a3ef44 CR3: 00000001d4909000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000000
c ffff8801c78167d2
c ffff8801cae4fc00
c 0000000000000046
c
 ffff8801cae4fb08
c ffff8801c789f338
c ffff8801cae4fa70
c ffffffff81243c87
c
 ffff8801cae4fb28
c 0000000000000046
c 0000000000000046
c ffff8801c7815f00
c
Call Trace:
 [<ffffffff810ec993>] do_wait_thread kernel/exit.c:1490 [inline]
 [<ffffffff810ec993>] do_wait+0x423/0x950 kernel/exit.c:1561
 [<ffffffff810eda0b>] SYSC_wait4 kernel/exit.c:1693 [inline]
 [<ffffffff810eda0b>] SyS_wait4+0x12b/0x1f0 kernel/exit.c:1658
 [<ffffffff812bf054>] C_SYSC_wait4 kernel/compat.c:543 [inline]
 [<ffffffff812bf054>] compat_SyS_wait4+0x254/0x290 kernel/compat.c:536
 [<ffffffff810c6305>] sys32_waitpid+0x25/0x30 arch/x86/ia32/sys_ia32.c:172
 [<ffffffff81006311>] do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline]
 [<ffffffff81006311>] do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390
 [<ffffffff82818de0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137
Code: 
c23 
c00 
c49 
c8d 
c5d 
c28 
c48 
cb8 
c00 
c00 
c00 
c00 
c00 
cfc 
cff 
cdf 
c48 
c89 
cda 
c48 
cc1 
cea 
c03 
c0f 
cb6 
c04 
c02 
c84 
cc0 
c74 
c08 
c3c 
c03 
c0f 
c8e 
c26 
c14 
c00 
c00 
c45 
c8b 
c5d 
c28 
c<45> 
c85 
cdb 
c0f 
c85 
c34 
c15 
c00 
c00 
ce8 
c09 
c28 
c23 
c00 
c41 
c83 
cfc 
c20 
c0f 
c84 
c09 
c