INFO: task syz-executor.1:29345 blocked for more than 140 seconds.
      Not tainted 4.9.194+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D27424 29345   2298 0x00000004
 0000000000000087 ffff8801d1e3c740 ffff8801d4b54200 ffff8801db621000
 ffff8801c2128000 ffff8801db621018 ffff8801c9ae79f8 ffffffff8281af8e
 ffff8801d1e3d008 ffff8801d1e3cfe0 00ff8801d1e3d010 ffff8801db6218f0
Call Trace:
 [<00000000e11898db>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<000000000cfb4573>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579
 [<00000000431c2da9>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<00000000431c2da9>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621
 [<000000008e472263>] pipe_lock_nested fs/pipe.c:66 [inline]
 [<000000008e472263>] pipe_lock fs/pipe.c:74 [inline]
 [<000000008e472263>] pipe_wait+0x1b8/0x1e0 fs/pipe.c:122
 [<000000008a52003c>] pipe_write+0x522/0xe40 fs/pipe.c:489
 [<000000002714cfff>] new_sync_write fs/read_write.c:498 [inline]
 [<000000002714cfff>] __vfs_write+0x3c1/0x560 fs/read_write.c:511
 [<00000000f6c72ace>] vfs_write+0x185/0x520 fs/read_write.c:559
 [<000000008f956fcc>] SYSC_write fs/read_write.c:607 [inline]
 [<000000008f956fcc>] SyS_write+0x121/0x270 fs/read_write.c:599
 [<00000000aa230fa4>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
 [<00000000514d589f>] 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: [<00000000081b8d22>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline]
 #0:  (rcu_read_lock){......}, at: [<00000000081b8d22>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263
 #1:  (tasklist_lock){.+.+..}, at: [<00000000e1f9c825>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336
2 locks held by getty/2019:
 #0:  (&tty->ldisc_sem){++++++}, at: [<0000000043d4ad81>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<0000000025e6053b>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.1/29345:
 #0:  (&pipe->mutex/1){+.+.+.}, at: [<000000008e472263>] pipe_lock_nested fs/pipe.c:66 [inline]
 #0:  (&pipe->mutex/1){+.+.+.}, at: [<000000008e472263>] pipe_lock fs/pipe.c:74 [inline]
 #0:  (&pipe->mutex/1){+.+.+.}, at: [<000000008e472263>] pipe_wait+0x1b8/0x1e0 fs/pipe.c:122

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

NMI backtrace for cpu 0
CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.194+ #0
 ffff8801d98efcc8 ffffffff81b67001 0000000000000000 0000000000000000
 0000000000000000 ffffffff81099d01 dffffc0000000000 ffff8801d98efd00
 ffffffff81b7229c 0000000000000000 0000000000000000 0000000000000000
Call Trace:
 [<00000000e29e8e9e>] __dump_stack lib/dump_stack.c:15 [inline]
 [<00000000e29e8e9e>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<00000000be09f74d>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99
 [<000000002df0ba20>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60
 [<000000005f9135de>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<00000000e7c10ba1>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<00000000e7c10ba1>] check_hung_task kernel/hung_task.c:126 [inline]
 [<00000000e7c10ba1>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline]
 [<00000000e7c10ba1>] watchdog+0x670/0xaf0 kernel/hung_task.c:263
 [<0000000040535d3e>] kthread+0x278/0x310 kernel/kthread.c:211
 [<000000005aacdcbf>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 29356 Comm: syz-executor.1 Not tainted 4.9.194+ #0
task: 00000000d9075b25 task.stack: 000000005a718155
RIP: 0010:[<ffffffff8120da6a>] 
c [<00000000f9ca132e>] __lock_acquire+0x96a/0x4390 kernel/locking/lockdep.c:3204
RSP: 0018:ffff8801c541f770  EFLAGS: 00000082
RAX: ffffed0038a83f02 RBX: 0000000045432540 RCX: 000000007a44f18e
RDX: 1ffff10038425115 RSI: ffff8801c21288d8 RDI: 0000000000000000
RBP: ffff8801c541f900 R08: 0000000000000001 R09: ffff8801c21288f8
R10: ffff8801c21288d8 R11: 0000000000000001 R12: 00000000cff7692b
R13: 000000002f95f72c R14: 0f2c18bb153a8e6b R15: ffff8801c2128000
FS:  00007f94556f5700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000201e2000 CR3: 00000001c566d000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff82e3d9c0
c ffffffff814a1710
c 0000000000000000
c fedf730c477737fc
c
 0000000000000246
c 00000001cd00e025
c 0000000000000000
c 0000000000000000
c
 0000000000000000
c ffff8801c541f830
c 0000000000000246
c 0000000000000000
c
Call Trace:
 [<0000000067c190b0>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3756
 [<00000000b11e095a>] down_read_trylock kernel/locking/rwsem.c:38 [inline]
 [<00000000b11e095a>] down_read_trylock+0x6a/0xd0 kernel/locking/rwsem.c:33
 [<00000000c61ef9ec>] __do_page_fault+0x25e/0xa60 arch/x86/mm/fault.c:1330
 [<00000000d28bc8b3>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1464
 [<00000000edc8e16e>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:956
 [<00000000fc7dc340>] pipe_to_user+0xb0/0x160 fs/splice.c:1256
 [<0000000003393363>] splice_from_pipe_feed fs/splice.c:521 [inline]
 [<0000000003393363>] __splice_from_pipe+0x351/0x790 fs/splice.c:645
 [<00000000e69d9044>] vmsplice_to_user+0x1bd/0x1e0 fs/splice.c:1291
 [<00000000da76321d>] SYSC_vmsplice fs/splice.c:1370 [inline]
 [<00000000da76321d>] SyS_vmsplice+0x114/0x140 fs/splice.c:1353
 [<00000000aa230fa4>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288
 [<00000000514d589f>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c