INFO: task syz-executor0:6046 blocked for more than 120 seconds.
      Not tainted 4.9.72-gcb7518e #114
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D29184  6046   3545 0x00000004
 ffff8801c5fb6000 0000000000000000 ffff8801c645aa00 ffff8801c5fb3000
 ffff8801db221458 ffff8801c7f07740 ffffffff8389e5fb ffff8801c7f07718
 ffffffff8123940f 00ffffff838a9f6a ffff8801db221d28 ffff8801db221d50
Call Trace:
 [<ffffffff8389fb9f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3550
 [<ffffffff838aa080>] rwsem_down_read_failed+0x1e0/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81dc5448>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff838a8e02>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff838a8e02>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff8200f7a5>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592
 [<ffffffff82010651>] tty_mode_ioctl+0x931/0x9c0 drivers/tty/tty_ioctl.c:970
 [<ffffffff82010780>] n_tty_ioctl_helper+0x40/0x360 drivers/tty/tty_ioctl.c:1161
 [<ffffffff82004348>] n_tty_ioctl+0x148/0x2d0 drivers/tty/n_tty.c:2437
 [<ffffffff81ffd153>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815abdda>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815abdda>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815acdff>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815acdff>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838af585>] entry_SYSCALL_64_fastpath+0x23/0xc6

Showing all locks held in the system:
2 locks held by khungtaskd/514:
 #0:  (rcu_read_lock){......}, at: [<ffffffff81371095>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81371095>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81236180>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
2 locks held by getty/3305:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838ad792>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff82007014>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor0/6046:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838ad792>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&o_tty->termios_rwsem/1){++++.+}, at: [<ffffffff8200f7a5>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592

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

NMI backtrace for cpu 0
CPU: 0 PID: 514 Comm: khungtaskd Not tainted 4.9.72-gcb7518e #114
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d9bf7d00 ffffffff81d922b9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810ba190 ffff8801d9bf7d38
 ffffffff81d9d3dd 0000000000000000 0000000000000000 ffff8801c6756418
Call Trace:
 [<ffffffff81d922b9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d922b9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9d3dd>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9d517>] 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
 [<ffffffff81371660>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81371660>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81371660>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81371660>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119898d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838af82a>] 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: 6023 Comm: syz-executor0 Not tainted 4.9.72-gcb7518e #114
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801b4b18000 task.stack: ffff8801b4a70000
RIP: 0010:[<ffffffff8136945f>] 
c [<ffffffff8136945f>] __sanitizer_cov_trace_pc+0x3f/0x50 kernel/kcov.c:105
RSP: 0018:ffff8801b4a77b28  EFLAGS: 00000216
RAX: 0000000000010000 RBX: ffffc90004d76060 RCX: ffffffff82004466
RDX: 0000000000010000 RSI: ffffc90000aa3000 RDI: ffffc90004d77260
RBP: ffff8801b4a77b28 R08: 1ffff1003696311a R09: 0000000000000000
R10: 0000000000000003 R11: ffff8801b4b18000 R12: ffffc90004d75000
R13: 00000006fc8dc6a6 R14: 0000000020de8000 R15: ffff8801c5fd1338
FS:  00007f1ad9b7c700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f15fcf1318c CR3: 00000001cf568000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801b4a77b78
c ffffffff82004466
c ffffffffffffeffa
c 00000000000006a6
c
 0000000000000000
c ffff8801c5fd1100
c 1ffff1003694ef75
c 000000000000541b
c
 ffffffffffffffe7
c ffff8801c7e93a00
c ffff8801b4a77d70
c ffffffff81ffd153
c
Call Trace:
 [<ffffffff82004466>] inq_canon drivers/tty/n_tty.c:2414 [inline]
 [<ffffffff82004466>] n_tty_ioctl+0x266/0x2d0 drivers/tty/n_tty.c:2431
 [<ffffffff81ffd153>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815abdda>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815abdda>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815acdff>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815acdff>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838af585>] entry_SYSCALL_64_fastpath+0x23/0xc6
Code: 
c81 
ce2 
c00 
c01 
c1f 
c00 
c48 
c8b 
c4d 
c08 
c75 
c2b 
c8b 
c90 
c68 
c12 
c00 
c00 
c83 
cfa 
c02 
c75 
c20 
c48 
c8b 
cb0 
c70 
c12 
c00 
c00 
c8b 
c80 
c6c 
c12 
c00 
c00 
c48 
c8b 
c16 
c48 
c83 
cc2 
c01 
c<48> 
c39 
cd0 
c76 
c07 
c48 
c89 
c0c 
cd6 
c48 
c89 
c16 
c5d 
cc3 
c0f 
c1f 
c00 
c55 
c48 
c89 
ce5 
c