Buffer I/O error on dev loop0, logical block 0, async page read
INFO: task syz-executor5:29758 blocked for more than 120 seconds.
      Not tainted 4.9.67-gf26d3c7 #106
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D29256 29758   3525 0x00000004
 ffff8801caf7b000 ffff8801c70cb480 ffff8801c70cb480 ffff8801d5acc800
 ffff8801db321418 ffff8801c4c5f740 ffffffff838981cb ffff8801c4c5f718
 ffffffff8123885f 00ffffff838a3b3a ffff8801db321ce8 ffff8801db321d10
Call Trace:
 [<ffffffff8389976f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3550
 [<ffffffff838a3c50>] rwsem_down_read_failed+0x1e0/0x320 kernel/locking/rwsem-xadd.c:260
 [<ffffffff81dc3878>] call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 [<ffffffff838a29d2>] __down_read arch/x86/include/asm/rwsem.h:65 [inline]
 [<ffffffff838a29d2>] down_read+0x52/0xb0 kernel/locking/rwsem.c:24
 [<ffffffff8200a4b5>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592
 [<ffffffff8200b361>] tty_mode_ioctl+0x931/0x9c0 drivers/tty/tty_ioctl.c:970
 [<ffffffff8200b490>] n_tty_ioctl_helper+0x40/0x360 drivers/tty/tty_ioctl.c:1161
 [<ffffffff81fff058>] n_tty_ioctl+0x148/0x2d0 drivers/tty/n_tty.c:2437
 [<ffffffff81ff7e93>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815aa59a>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815aa59a>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815ab5bf>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815ab5bf>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838a9985>] entry_SYSCALL_64_fastpath+0x23/0xc6

Showing all locks held in the system:
2 locks held by khungtaskd/514:
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fe05>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff8136fe05>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.?..}, at: [<ffffffff812355d0>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
2 locks held by getty/3248:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a7b92>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff82001d24>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
2 locks held by syz-executor5/29758:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a7b92>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&o_tty->termios_rwsem/1){++++..}, at: [<ffffffff8200a4b5>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592
3 locks held by syz-executor5/29781:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a7b92>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff82001d24>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
 #2:  (&o_tty->termios_rwsem/1){++++..}, at: [<ffffffff82001d47>] n_tty_read+0x217/0x16c0 drivers/tty/n_tty.c:2137
2 locks held by syz-executor5/29790:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838a7b92>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&o_tty->termios_rwsem/1){++++..}, at: [<ffffffff8200a4b5>] set_termios+0xf5/0x670 drivers/tty/tty_ioctl.c:592

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

NMI backtrace for cpu 1
CPU: 1 PID: 514 Comm: khungtaskd Not tainted 4.9.67-gf26d3c7 #106
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d9a2fd00 ffffffff81d906e9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810ba170 ffff8801d9a2fd38
 ffffffff81d9b80d 0000000000000001 0000000000000000 ffff8801d5ac9c18
Call Trace:
 [<ffffffff81d906e9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d906e9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9b80d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9b947>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810ba264>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff813703d0>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff813703d0>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813703d0>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813703d0>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff811985ad>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838a9c2a>] 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: 29750 Comm: syz-executor5 Not tainted 4.9.67-gf26d3c7 #106
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d5acc800 task.stack: ffff8801c6840000
RIP: 0010:[<ffffffff813681ee>] 
c [<ffffffff813681ee>] __sanitizer_cov_trace_pc+0x2e/0x60 kernel/kcov.c:88
RSP: 0018:ffff8801c6847b28  EFLAGS: 00000246
RAX: ffff8801d5acc800 RBX: ffffc90000903060 RCX: ffffc900026d2000
RDX: 0000000000000001 RSI: 0000000017af5d69 RDI: ffffc90000904260
RBP: ffff8801c6847b28 R08: 1ffff1003ab59a1a R09: 0000000000000000
R10: 0000000000000003 R11: ffff8801d5acc800 R12: ffffc90000902000
R13: 00000005bf11c822 R14: 0000000020476ffc R15: ffff8801a5b6e838
FS:  00007f07e7456700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000024f0000 CR3: 00000001a8d61000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801c6847b78
c ffffffff81fff176
c ffffffffffffffff
c 0000000000000822
c
 0000000000000000
c ffff8801a5b6e600
c 1ffff10038d08f75
c 000000000000541b
c
 ffffffffffffffe7
c ffff8801ca188a00
c ffff8801c6847d70
c ffffffff81ff7e93
c
Call Trace:
 [<ffffffff81fff176>] inq_canon drivers/tty/n_tty.c:2414 [inline]
 [<ffffffff81fff176>] n_tty_ioctl+0x266/0x2d0 drivers/tty/n_tty.c:2431
 [<ffffffff81ff7e93>] tty_ioctl+0x733/0x2170 drivers/tty/tty_io.c:2992
 [<ffffffff815aa59a>] vfs_ioctl fs/ioctl.c:43 [inline]
 [<ffffffff815aa59a>] do_vfs_ioctl+0x1aa/0x1140 fs/ioctl.c:679
 [<ffffffff815ab5bf>] SYSC_ioctl fs/ioctl.c:694 [inline]
 [<ffffffff815ab5bf>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 [<ffffffff838a9985>] entry_SYSCALL_64_fastpath+0x23/0xc6
Code: 
c8b 
c04 
c25 
c40 
c55 
c01 
c00 
c48 
c85 
cc0 
c48 
c89 
ce5 
c74 
c1a 
c65 
c8b 
c15 
cf7 
cd2 
cca 
c7e 
c81 
ce2 
c00 
c01 
c1f 
c00 
c75 
c0b 
c8b 
c90 
c68 
c12 
c00 
c00 
c83 
cfa 
c01 
c74 
c02 
c5d 
cc3 
c<48> 
c8b 
c88 
c70 
c12 
c00 
c00 
c8b 
c80 
c6c 
c12 
c00 
c00 
c48 
c8b 
c11 
c48 
c83 
cc2 
c01 
c48 
c