INFO: task syz-executor7:7331 blocked for more than 120 seconds.
      Not tainted 4.9.73-gf3f3457 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor7   D29424  7331   3568 0x00000004
 ffff8801c3964800 ffff8801c574c000 ffff8801c574c000 ffff8801b4009800
 ffff8801db221458 ffff8801b47b7740 ffffffff8389e5fb ffff8801b47b7718
 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/3302:
 #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-executor7/7331:
 #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 1
CPU: 1 PID: 514 Comm: khungtaskd Not tainted 4.9.73-gf3f3457 #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8a6fd00 ffffffff81d922b9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810ba190 ffff8801d8a6fd38
 ffffffff81d9d3dd 0000000000000001 0000000000000000 ffff8801c393cc18
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7302 Comm: syz-executor7 Not tainted 4.9.73-gf3f3457 #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801b4009800 task.stack: ffff8801c3848000
RIP: 0010:[<ffffffff81369421>] 
c [<ffffffff81369421>] __sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:93
RSP: 0018:ffff8801c384fb28  EFLAGS: 00000202
RAX: 00000000000001f4 RBX: ffffc90004f96060 RCX: ffffffff8200440c
RDX: 0000000000010000 RSI: ffffc90001186000 RDI: ffffc90004f97260
RBP: ffff8801c384fb78 R08: 1ffff1003680141a R09: 0000000000000000
R10: 0000000000000003 R11: ffff8801b4009800 R12: ffffc90004f95000
R13: 000000070fca81f4 R14: 0000000020f77000 R15: ffff8801c4a3f0b8
FS:  00007f590f61f700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f826c9dd000 CR3: 00000001d02b5000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801c384fb78
c ffffffff82004466
c ffffffffffffeffa
c 00000000000001f4
c
 0000000000000000
c ffff8801c4a3ee80
c 1ffff10038709f75
c 000000000000541b
c
 ffffffffffffffe7
c ffff8801c67cf400
c ffff8801c384fd70
c ffffffff81ffd153
c
Call Trace:
 [<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: 
c00 
ceb 
c81 
c4c 
c89 
cff 
ce8 
cbf 
c2d 
c1d 
c00 
ce9 
c5f 
cff 
cff 
cff 
c48 
c89 
cdf 
ce8 
c12 
c2d 
c1d 
c00 
ce9 
c29 
cff 
cff 
cff 
c66 
c2e 
c0f 
c1f 
c84 
c00 
c00 
c00 
c00 
c00 
c0f 
c1f 
c00 
c55 
c<48> 
c89 
ce5 
c65 
c48 
c8b 
c04 
c25 
c40 
c55 
c01 
c00 
c65 
c8b 
c15 
c9c 
cc0 
cca 
c7e 
c81 
ce2 
c