INFO: task syz-executor2:32011 blocked for more than 140 seconds.
      Not tainted 4.9.131+ #50
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor2   D29896 32011  32010 0x00000000
 ffff8801cb08df00 0000000000000000 ffff8801c579dd80 ffff8801cb08af80
 ffff8801db621018 ffff88018d457c88 ffffffff827f3542 0000000000000000
 ffff8801cb08e7b0 ffffed0039611cf5 00ff8801cb08df00 ffff8801db6218f0
Call Trace:
 [<ffffffff827f4a6f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff827f53f3>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3586
 [<ffffffff827f746d>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff827f746d>] mutex_lock_nested+0x38d/0x900 kernel/locking/mutex.c:621
 [<ffffffff815269e0>] __pipe_lock fs/pipe.c:87 [inline]
 [<ffffffff815269e0>] pipe_release+0x50/0x250 fs/pipe.c:568
 [<ffffffff815103c3>] __fput+0x263/0x700 fs/file_table.c:208
 [<ffffffff815108e5>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff8113da0c>] task_work_run+0x10c/0x180 kernel/task_work.c:116
 [<ffffffff81003e49>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<ffffffff81003e49>] exit_to_usermode_loop+0x129/0x150 arch/x86/entry/common.c:162
 [<ffffffff81005932>] prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 [<ffffffff81005932>] syscall_return_slowpath arch/x86/entry/common.c:263 [inline]
 [<ffffffff81005932>] do_syscall_64+0x3e2/0x550 arch/x86/entry/common.c:290
 [<ffffffff828037d3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/24:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bbcc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8131bbcc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.?..}, at: [<ffffffff813fe394>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/2025:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82801892>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff81d2b2b2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor2/32010:
 #0:  (&pipe->mutex/1){+.+.+.}, at: [<ffffffff81523d4e>] pipe_lock_nested fs/pipe.c:66 [inline]
 #0:  (&pipe->mutex/1){+.+.+.}, at: [<ffffffff81523d4e>] pipe_lock+0x5e/0x70 fs/pipe.c:74
1 lock held by syz-executor2/32011:
 #0:  (&pipe->mutex/1){+.+.+.}, at: [<ffffffff815269e0>] __pipe_lock fs/pipe.c:87 [inline]
 #0:  (&pipe->mutex/1){+.+.+.}, at: [<ffffffff815269e0>] pipe_release+0x50/0x250 fs/pipe.c:568

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.131+ #50
 ffff8801d9907d08 ffffffff81b37029 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff81098450 ffff8801d9907d40
 ffffffff81b42139 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81b37029>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81b37029>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81b42139>] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81b420cc>] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60
 [<ffffffff81098554>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff8131c15d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff8131c15d>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff8131c15d>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff8131c15d>] watchdog+0x6ad/0xa20 kernel/hung_task.c:239
 [<ffffffff811429fd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff8280399c>] 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: 0 Comm: swapper/0 Not tainted 4.9.131+ #50
task: ffffffff83029180 task.stack: ffffffff83000000
RIP: 0010:[<ffffffff8120cceb>] 
c [<ffffffff8120cceb>] __lock_release kernel/locking/lockdep.c:3550 [inline]
RIP: 0010:[<ffffffff8120cceb>] 
c [<ffffffff8120cceb>] lock_release+0x39b/0xc20 kernel/locking/lockdep.c:3775
RSP: 0018:ffff8801db607e88  EFLAGS: 00000046
RAX: 0000000000000003 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff83029a30 RDI: 0000000000000000
RBP: ffff8801db607f30 R08: ffffffff83029a50 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffffff83029a30 R14: ffffffff83029a08 R15: ffffffff83029a52
FS:  0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000c2f978 CR3: 00000001a912f000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Stack:
 093622b1e709bef8
c 0000000000000046
c ffffffff83029180
c 0000000000000000
c
 0000000000000000
c 0000000000000002
c ffff8801db607f30
c 0000000000000046
c
 0000000000000000
c ffffffff83029a28
c ffffffff83029a30
c 0000000000000046
c
Call Trace:
 [<ffffffff8127c53f>] seqcount_lockdep_reader_access include/linux/seqlock.h:81 [inline]
 [<ffffffff8127c53f>] read_seqcount_begin include/linux/seqlock.h:163 [inline]
 [<ffffffff8127c53f>] ktime_get+0x12f/0x1e0 kernel/time/timekeeping.c:757
 [<ffffffff81296b0c>] tick_nohz_irq_enter kernel/time/tick-sched.c:1144 [inline]
 [<ffffffff81296b0c>] tick_irq_enter+0xcc/0x220 kernel/time/tick-sched.c:1165
 [<ffffffff810efb13>] irq_enter+0xb3/0xd0 kernel/softirq.c:349
 [<ffffffff828065fa>] smp_reschedule_interrupt+0xa/0x90 arch/x86/kernel/smp.c:267
 [<ffffffff828054ed>] reschedule_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:671
 <EOI> 
d [<ffffffff828023d6>] ? native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:56
 [<ffffffff82801935>] arch_safe_halt arch/x86/include/asm/paravirt.h:104 [inline]
 [<ffffffff82801935>] default_idle+0x55/0x360 arch/x86/kernel/process.c:437
 [<ffffffff81068910>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:428
 [<ffffffff82802835>] default_idle_call+0x45/0x60 kernel/sched/idle.c:97
 [<ffffffff811f0865>] cpuidle_idle_call kernel/sched/idle.c:155 [inline]
 [<ffffffff811f0865>] cpu_idle_loop kernel/sched/idle.c:248 [inline]
 [<ffffffff811f0865>] cpu_startup_entry+0x2b5/0x380 kernel/sched/idle.c:303
 [<ffffffff827f0e2c>] rest_init+0x183/0x189 init/main.c:409
 [<ffffffff8341991b>] start_kernel+0x5fb/0x62f init/main.c:664
 [<ffffffff8341829a>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196
 [<ffffffff834183d6>] x86_64_start_kernel+0x13a/0x15d arch/x86/kernel/head64.c:177
Code: 
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c