INFO: task syz-executor.5:17567 blocked for more than 140 seconds.
      Not tainted 4.9.141+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D29592 17567  17566 0x00000000
 ffff8801d49a97c0 0000000000000000 ffff8801a8606e00 ffffffff83029180
 ffff8801db621018 ffff8801c4e0f840 ffffffff828075c2 ffff880100000001
 ffffffff00000000 fffffbfff08489a8 00229aa300000001 ffff8801db6218f0
Call Trace:
 [<ffffffff82808aef>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff828142d5>] schedule_timeout+0x735/0xe20 kernel/time/timer.c:1771
 [<ffffffff81d4312c>] down_read_failed drivers/tty/tty_ldsem.c:241 [inline]
 [<ffffffff81d4312c>] __ldsem_down_read_nested+0x33c/0x610 drivers/tty/tty_ldsem.c:332
 [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 [<ffffffff81d3ca85>] tty_ldisc_ref_wait+0x25/0x80 drivers/tty/tty_ldisc.c:275
 [<ffffffff81d28626>] tty_ioctl+0x3b6/0x2190 drivers/tty/tty_io.c:3009
 [<ffffffff81546dec>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff81546dec>] file_ioctl fs/ioctl.c:493 [inline]
 [<ffffffff81546dec>] do_vfs_ioctl+0x1ac/0x11a0 fs/ioctl.c:677
 [<ffffffff81547e6f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff81547e6f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82817893>] 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: [<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/2032:
 #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
2 locks held by syz-executor.5/17566:
 #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.5/17567:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff82815952>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
1 lock held by syz-executor.1/5374:
 #0:  (sk_lock-AF_PACKET){+.+.+.}, at: [<ffffffff827d1f3f>] lock_sock include/net/sock.h:1404 [inline]
 #0:  (sk_lock-AF_PACKET){+.+.+.}, at: [<ffffffff827d1f3f>] packet_setsockopt+0x50f/0x2630 net/packet/af_packet.c:3668

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

NMI backtrace for cpu 1
CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.141+ #1
 ffff8801d9907d08 ffffffff81b42e79 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810983b0 ffff8801d9907d40
 ffffffff81b4df89 0000000000000001 0000000000000000 0000000000000002
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: 5382 Comm: syz-executor.5 Not tainted 4.9.141+ #1
task: ffff8801d6794740 task.stack: ffff8801a1fd0000
RIP: 0010:[<ffffffff814be265>] 
c [<ffffffff814be265>] __read_once_size include/linux/compiler.h:243 [inline]
RIP: 0010:[<ffffffff814be265>] 
c [<ffffffff814be265>] compound_head include/linux/page-flags.h:143 [inline]
RIP: 0010:[<ffffffff814be265>] 
c [<ffffffff814be265>] __SetPageSwapBacked include/linux/page-flags.h:279 [inline]
RIP: 0010:[<ffffffff814be265>] 
c [<ffffffff814be265>] page_add_new_anon_rmap+0x95/0x190 mm/rmap.c:1285
RSP: 0018:ffff8801a1fd75b0  EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffea000611b0c0 RCX: ffffc90001555000
RDX: 1ffffd4000c2361c RSI: ffffffff814be24c RDI: ffffea000611b0e0
RBP: ffff8801a1fd75e0 R08: ffff8801d6794ff0 R09: 9b7e0649fa0d6596
R10: ffff8801d6794740 R11: 0000000000000001 R12: ffff8801d387ee10
R13: 00000000206c3000 R14: ffffea000611b0c0 R15: 0000000000000000
FS:  00007f6b569fa700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000206c3000 CR3: 00000001c97fd000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d959d618
c ffff8801a1fd7930
c 0000000000000000
c 00000001846c3067
c
 ffffea000611b0c0
c ffff8801a1fd7950
c ffff8801a1fd76c8
c ffffffff81493e86
c
 ffff8801a1fd7958
c ffff8801d2628108
c ffffea000611b0e0
c 1ffff100343faec8
c
Call Trace:
 [<ffffffff81493e86>] wp_page_copy+0x846/0x12a0 mm/memory.c:2207
 [<ffffffff814974b7>] do_wp_page+0x817/0x2010 mm/memory.c:2390
 [<ffffffff814a333b>] handle_pte_fault mm/memory.c:3531 [inline]
 [<ffffffff814a333b>] __handle_mm_fault mm/memory.c:3603 [inline]
 [<ffffffff814a333b>] handle_mm_fault+0xfcb/0x2350 mm/memory.c:3640
 [<ffffffff810b2b33>] __do_page_fault+0x403/0xa60 arch/x86/mm/fault.c:1406
 [<ffffffff810b31e7>] do_page_fault+0x27/0x30 arch/x86/mm/fault.c:1469
 [<ffffffff828188b5>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:951
 [<ffffffff81525db7>] pipe_read+0x467/0x810 fs/pipe.c:284
 [<ffffffff81507de4>] new_sync_read fs/read_write.c:439 [inline]
 [<ffffffff81507de4>] __vfs_read+0x3d4/0x560 fs/read_write.c:451
 [<ffffffff8150a7a4>] vfs_read+0x124/0x390 fs/read_write.c:472
 [<ffffffff8150e809>] SYSC_read fs/read_write.c:588 [inline]
 [<ffffffff8150e809>] SyS_read+0xd9/0x1c0 fs/read_write.c:581
 [<ffffffff810056ef>] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285
 [<ffffffff82817893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 
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c