INFO: task syz-executor5:13807 blocked for more than 120 seconds.
      Not tainted 4.9.71-g319c8e1 #111
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D28304 13807   3567 0x00000004
 ffff8801c9fbc800 0000000000000000 ffff8801ca156f40 ffffffff84426880
 ffff8801db221458 ffff8801c87b7740 ffffffff83899d2b ffff8801c87b7718
 ffffffff8123905f 00ffffff838a569a ffff8801db221d28 ffff8801db221d50
Call Trace:
 [<ffffffff8389b2cf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3550
 [<ffffffff838a57b0>] rwsem_down_read_failed+0x1e0/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81dc47c8>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff838a4532>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff838a4532>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff8200b415>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592
 [<ffffffff8200c2c1>] tty_mode_ioctl+0x931/0x9c0 drivers/tty/tty_ioctl.c:970
 [<ffffffff8200c3f0>] n_tty_ioctl_helper+0x40/0x360 drivers/tty/tty_ioctl.c:1161
 [<ffffffff81ffffb8>] n_tty_ioctl+0x148/0x2d0 drivers/tty/n_tty.c:2437
 [<ffffffff81ff8df3>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815ab25a>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815ab25a>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815ac27f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815ac27f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838ab505>] entry_SYSCALL_64_fastpath+0x23/0xc6

Showing all locks held in the system:
2 locks held by khungtaskd/514:
 #0:  (rcu_read_lock){......}, at: [<ffffffff81370635>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81370635>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81235dd0>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
2 locks held by getty/3290:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a96f2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff82002c84>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor5/13807:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a96f2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&o_tty->termios_rwsem/1){++++.+}, at: [<ffffffff8200b415>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592

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

NMI backtrace for cpu 0
CPU: 0 PID: 514 Comm: khungtaskd Not tainted 4.9.71-g319c8e1 #111
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8897d00 ffffffff81d91639 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810ba190 ffff8801d8897d38
 ffffffff81d9c75d 0000000000000000 0000000000000000 ffff8801c99c8418
Call Trace:
 [<ffffffff81d91639>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d91639>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9c75d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9c897>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810ba284>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81370c00>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81370c00>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81370c00>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81370c00>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff811985ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838ab7aa>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 13782 Comm: syz-executor5 Not tainted 4.9.71-g319c8e1 #111
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801c8573000 task.stack: ffff8801c7c38000
RIP: 0010:[<ffffffff813689e0>] 
c [<ffffffff813689e0>] check_kcov_mode kernel/kcov.c:66 [inline]
RIP: 0010:[<ffffffff813689e0>] 
c [<ffffffff813689e0>] __sanitizer_cov_trace_pc+0x20/0x50 kernel/kcov.c:100
RSP: 0018:ffff8801c7c3fb28  EFLAGS: 00000246
RAX: ffff8801c8573000 RBX: ffffc90006740060 RCX: ffffffff8200007c
RDX: 0000000000000000 RSI: ffffc90003150000 RDI: ffffc90006741260
RBP: ffff8801c7c3fb28 R08: 1ffff100390ae71a R09: 0000000000000000
R10: 0000000000000003 R11: ffff8801c8573000 R12: ffffc9000673f000
R13: 00000006accc6c92 R14: 0000000020a2cffc R15: ffff8801c945d738
FS:  00007ffaf2cf1700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f21e04789b8 CR3: 00000001cdccd000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801c7c3fb78
c ffffffff8200007c
c ffffffffffffeffa
c 0000000000000c91
c
 0000000000000000
c ffff8801c945d500
c 1ffff10038f87f75
c 000000000000541b
c
 ffffffffffffffe7
c ffff8801c8d86800
c ffff8801c7c3fd70
c ffffffff81ff8df3
c
Call Trace:
 [<ffffffff8200007c>] inq_canon drivers/tty/n_tty.c:2411 [inline]
 [<ffffffff8200007c>] n_tty_ioctl+0x20c/0x2d0 drivers/tty/n_tty.c:2431
 [<ffffffff81ff8df3>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815ab25a>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815ab25a>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815ac27f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815ac27f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838ab505>] entry_SYSCALL_64_fastpath+0x23/0xc6
Code: 
c0f 
c1f 
c84 
c00 
c00 
c00 
c00 
c00 
c0f 
c1f 
c00 
c55 
c48 
c89 
ce5 
c65 
c48 
c8b 
c04 
c25 
c40 
c55 
c01 
c00 
c65 
c8b 
c15 
cfc 
cca 
cca 
c7e 
c81 
ce2 
c00 
c01 
c1f 
c00 
c48 
c8b 
c4d 
c08 
c75 
c2b 
c<8b> 
c90 
c68 
c12 
c00 
c00 
c83 
cfa 
c02 
c75 
c20 
c48 
c8b 
cb0 
c70 
c12 
c00 
c00 
c8b 
c80 
c6c 
c