INFO: task syz-executor5:4839 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-executor5   D28960  4839   3562 0x00000004
 ffff8801cec39800 ffff8801cec42f40 ffff8801cecb4000 ffff8801cef4e000
 ffff8801db321458 ffff8801ce4377d0 ffffffff8389e5fb ffff8801ce4377a8
 ffffffff8123940f 00ffffff838a9f6a ffff8801db321d28 ffff8801db321d50
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
 [<ffffffff82007037>] n_tty_read+0x217/0x16c0 drivers/tty/n_tty.c:2137
 [<ffffffff81ff5859>] tty_read+0x169/0x250 drivers/tty/tty_io.c:1079
 [<ffffffff8156a4e1>] do_loop_readv_writev.part.17+0x141/0x1e0 fs/read_write.c:714
 [<ffffffff8156e350>] do_loop_readv_writev fs/read_write.c:880 [inline]
 [<ffffffff8156e350>] do_readv_writev+0x520/0x750 fs/read_write.c:874
 [<ffffffff8156e604>] vfs_readv+0x84/0xc0 fs/read_write.c:898
 [<ffffffff8156e726>] do_readv+0xe6/0x250 fs/read_write.c:924
 [<ffffffff81571c17>] SYSC_readv fs/read_write.c:1011 [inline]
 [<ffffffff81571c17>] SyS_readv+0x27/0x30 fs/read_write.c:1008
 [<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/3313:
 #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
3 locks held by syz-executor5/4839:
 #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:  (&o_tty->termios_rwsem/1){++++..}, at: [<ffffffff82007037>] n_tty_read+0x217/0x16c0 drivers/tty/n_tty.c:2137
2 locks held by syz-executor5/4862:
 #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
 ffff8801d9bc7d00 ffffffff81d922b9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810ba190 ffff8801d9bc7d38
 ffffffff81d9d3dd 0000000000000001 0000000000000000 ffff8801d1af1c18
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: 4824 Comm: syz-executor5 Not tainted 4.9.73-gf3f3457 #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cef0b000 task.stack: ffff8801cf3d8000
RIP: 0010:[<ffffffff81369446>] 
c [<ffffffff81369446>] __read_once_size include/linux/compiler.h:243 [inline]
RIP: 0010:[<ffffffff81369446>] 
c [<ffffffff81369446>] check_kcov_mode kernel/kcov.c:68 [inline]
RIP: 0010:[<ffffffff81369446>] 
c [<ffffffff81369446>] __sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:100
RSP: 0018:ffff8801cf3dfb28  EFLAGS: 00000246
RAX: ffff8801cef0b000 RBX: ffffc90004d13060 RCX: ffffffff82004466
RDX: 0000000000000002 RSI: ffffc9000254d000 RDI: ffffc90004d14260
RBP: ffff8801cf3dfb28 R08: 1ffff10039de171a R09: 0000000000000000
R10: 0000000000000003 R11: ffff8801cef0b000 R12: ffffc90004d12000
R13: 0000000709aaabab R14: 0000000020fbc000 R15: ffff8801cee92cb8
FS:  00007f3fb1a87700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcafbbd7000 CR3: 00000001d8fb1000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801cf3dfb78
c ffffffff82004466
c ffffffffffffffff
c 0000000000000bab
c
 0000000000000000
c ffff8801cee92a80
c 1ffff10039e7bf75
c 000000000000541b
c
 ffffffffffffffe7
c ffff8801cfa26600
c ffff8801cf3dfd70
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: 
c00 
c00 
c0f 
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c00 
c55 
c48 
c89 
ce5 
c65 
c48 
c8b 
c04 
c25 
c40 
c55 
c01 
c00 
c65 
c8b 
c15 
c9c 
cc0 
cca 
c7e 
c81 
ce2 
c00 
c01 
c1f 
c00 
c48 
c8b 
c4d 
c08 
c75 
c2b 
c8b 
c90 
c68 
c12 
c00 
c00 
c<83> 
cfa 
c02 
c75 
c20 
c48 
c8b 
cb0 
c70 
c12 
c00 
c00 
c8b 
c80 
c6c 
c12 
c00 
c00 
c48 
c8b 
c16 
c