INFO: task syz-executor1:12380 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-executor1   D29168 12380   3562 0x00000004
 ffff8801d0283000 ffff8801d6e4ea00 ffff8801d6e4ea00 ffff8801cfac8000
 ffff8801db321458 ffff8801d01c77d0 ffffffff8389e5fb ffff8801d01c77a8
 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/513:
 #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
3 locks held by syz-executor1/12380:
 #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

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

NMI backtrace for cpu 0
CPU: 0 PID: 513 Comm: khungtaskd Not tainted 4.9.72-gcb7518e #114
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8a47d00 ffffffff81d922b9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810ba190 ffff8801d8a47d38
 ffffffff81d9d3dd 0000000000000000 0000000000000000 ffff8801d0e48418
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: 12371 Comm: syz-executor1 Not tainted 4.9.72-gcb7518e #114
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cfac8000 task.stack: ffff8801d1140000
RIP: 0010:[<ffffffff8136945b>] 
c [<ffffffff8136945b>] __read_once_size include/linux/compiler.h:243 [inline]
RIP: 0010:[<ffffffff8136945b>] 
c [<ffffffff8136945b>] __sanitizer_cov_trace_pc+0x3b/0x50 kernel/kcov.c:105
RSP: 0018:ffff8801d1147b28  EFLAGS: 00000246
RAX: 0000000000010000 RBX: ffffc90005c5c060 RCX: ffffffff8200440c
RDX: 000000000000ffff RSI: ffffc9000173c000 RDI: ffffc90005c5d260
RBP: ffff8801d1147b28 R08: 1ffff10039f5911a R09: 0000000000000000
R10: 0000000000000003 R11: ffff8801cfac8000 R12: ffffc90005c5b000
R13: 00000005f9ae583e R14: 00000000203efffc R15: ffff8801d5593538
FS:  00007f6324741700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f38e43e3000 CR3: 00000001c91c0000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801d1147b78
c ffffffff8200440c
c ffffffffffffeff9
c 000000000000083d
c
 0000000000000000
c ffff8801d5593300
c 1ffff1003a228f75
c 000000000000541b
c
 ffffffffffffffe7
c ffff8801d02e3a00
c ffff8801d1147d70
c ffffffff81ffd153
c
Call Trace:
 [<ffffffff8200440c>] inq_canon drivers/tty/n_tty.c:2411 [inline]
 [<ffffffff8200440c>] n_tty_ioctl+0x20c/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: 
c9c 
cc0 
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