INFO: task syz-executor5:4197 blocked for more than 120 seconds.
      Not tainted 4.9.70-gc14c7b3 #110
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D29184  4197   3557 0x00000004
 ffff8801d6286000 ffff8801d5e4ca80 ffff8801d5e4ca80 ffff8801d6efb000
 ffff8801db321458 ffff8801d5b8f740 ffffffff83898c3b ffff8801d5b8f718
 ffffffff8123886f 00ffffff838a45aa ffff8801db321d28 ffff8801db321d50
Call Trace:
 [<ffffffff8389a1df>] schedule+0x7f/0x1b0 kernel/sched/core.c:3550
 [<ffffffff838a46c0>] rwsem_down_read_failed+0x1e0/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81dc3dd8>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff838a3442>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff838a3442>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff8200aa35>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592
 [<ffffffff8200b8e1>] tty_mode_ioctl+0x931/0x9c0 drivers/tty/tty_ioctl.c:970
 [<ffffffff8200ba10>] n_tty_ioctl_helper+0x40/0x360 drivers/tty/tty_ioctl.c:1161
 [<ffffffff81fff5d8>] n_tty_ioctl+0x148/0x2d0 drivers/tty/n_tty.c:2437
 [<ffffffff81ff8413>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815aaa0a>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815aaa0a>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815aba2f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815aba2f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838aa405>] entry_SYSCALL_64_fastpath+0x23/0xc6

Showing all locks held in the system:
2 locks held by khungtaskd/514:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fe45>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fe45>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff812355e0>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
2 locks held by getty/3297:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a8602>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff820022a4>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor5/4197:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a8602>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&o_tty->termios_rwsem/1){++++.+}, at: [<ffffffff8200aa35>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592

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

NMI backtrace for cpu 1
CPU: 1 PID: 514 Comm: khungtaskd Not tainted 4.9.70-gc14c7b3 #110
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8f17d00 ffffffff81d90c49 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810ba1a0 ffff8801d8f17d38
 ffffffff81d9bd6d 0000000000000001 0000000000000000 ffff8801d6194c18
Call Trace:
 [<ffffffff81d90c49>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d90c49>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9bd6d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9bea7>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810ba294>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81370410>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81370410>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81370410>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81370410>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff811985ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838aa6aa>] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4172 Comm: syz-executor5 Not tainted 4.9.70-gc14c7b3 #110
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d6efb000 task.stack: ffff8801d65c8000
RIP: 0010:[<ffffffff8136820b>] 
c [<ffffffff8136820b>] __read_once_size include/linux/compiler.h:243 [inline]
RIP: 0010:[<ffffffff8136820b>] 
c [<ffffffff8136820b>] __sanitizer_cov_trace_pc+0x3b/0x50 kernel/kcov.c:105
RSP: 0018:ffff8801d65cfb28  EFLAGS: 00000246
RAX: 0000000000010000 RBX: ffffc90004b82060 RCX: ffffffff81fff6f6
RDX: 000000000000ffff RSI: ffffc9000179a000 RDI: ffffc90004b83260
RBP: ffff8801d65cfb28 R08: 1ffff1003addf71a R09: 0000000000000000
R10: 0000000000000003 R11: ffff8801d6efb000 R12: ffffc90004b81000
R13: 000000085ede880c R14: 0000000020331ffc R15: ffff8801d5d99338
FS:  00007fda31122700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff560f9a000 CR3: 00000001da386000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d65cfb78
c ffffffff81fff6f6
c ffffffffffffeffa
c 000000000000080c
c
 0000000000000000
c ffff8801d5d99100
c 1ffff1003acb9f75
c 000000000000541b
c
 ffffffffffffffe7
c ffff8801d6470400
c ffff8801d65cfd70
c ffffffff81ff8413
c
Call Trace:
 [<ffffffff81fff6f6>] inq_canon drivers/tty/n_tty.c:2414 [inline]
 [<ffffffff81fff6f6>] n_tty_ioctl+0x266/0x2d0 drivers/tty/n_tty.c:2431
 [<ffffffff81ff8413>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815aaa0a>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815aaa0a>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815aba2f>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815aba2f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838aa405>] entry_SYSCALL_64_fastpath+0x23/0xc6
Code: 
cec 
cd2 
cca 
c7e 
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 
c<48> 
c83 
cc2 
c01 
c48 
c39 
cd0 
c76 
c07 
c48 
c89 
c0c 
cd6 
c48 
c89 
c16 
c5d 
cc3 
c0f 
c1f 
c00 
c