Buffer I/O error on dev loop5, logical block 3, async page read
INFO: task syz-executor6:14245 blocked for more than 120 seconds.
      Not tainted 4.9.57-g9eaaf14 #69
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor6   D28960 14245   3562 0x00000104
 ffff8801d8098000 ffff8801cd5aaf40 ffff8801cf694fc0 ffff8801ce90b000
 ffff8801db321518 ffff8801a9aff950 ffffffff8389887b ffffffff8123b9d0
 ffff8801d2052800 00ff8801d51f9a10 ffff8801db321e40 ffff8801db321e68
Call Trace:
 [<ffffffff83899e1f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3625
 [<ffffffff838a6053>] schedule_timeout+0x643/0x1220 kernel/time/timer.c:1770
 [<ffffffff8389802e>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:5243
 [<ffffffff8389b299>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff8389b299>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff8389a977>] __wait_on_bit+0x57/0x120 kernel/sched/wait.c:383
 [<ffffffff814317f4>] wait_on_page_bit+0xf4/0x140 mm/filemap.c:802
 [<ffffffff81431a01>] wait_on_page_writeback include/linux/pagemap.h:526 [inline]
 [<ffffffff81431a01>] __filemap_fdatawait_range+0x1c1/0x2b0 mm/filemap.c:453
 [<ffffffff8143b963>] filemap_fdatawait_keep_errors+0x63/0x80 mm/filemap.c:511
 [<ffffffff81613990>] fdatawait_one_bdev+0x50/0x70 fs/sync.c:94
 [<ffffffff8162f019>] iterate_bdevs+0x109/0x260 fs/block_dev.c:1978
 [<ffffffff81614261>] sys_sync+0xe1/0x170 fs/sync.c:116
 [<ffffffff81006517>] do_syscall_64+0x197/0x490 arch/x86/entry/common.c:280
 [<ffffffff838aa10d>] entry_SYSCALL64_slow_path+0x25/0x25
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 PID: 514 Comm: khungtaskd Not tainted 4.9.57-g9eaaf14 #69
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d8e3fd00 ffffffff81d91689 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810bd090 ffff8801d8e3fd38
 ffffffff81d9c7ad 0000000000000000 0000000000000000 ffff8801c81fcc18
Call Trace:
 [<ffffffff81d91689>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d91689>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81d9c7ad>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81d9c8e7>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810bd184>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81372790>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81372790>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81372790>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81372790>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119ad0d>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838aa2ea>] 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: 14393 Comm: init Not tainted 4.9.57-g9eaaf14 #69
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801cf916000 task.stack: ffff8801c69d8000
RIP: 0010:[<ffffffff820337bb>] 
c [<ffffffff820337bb>] inb arch/x86/include/asm/io.h:316 [inline]
RIP: 0010:[<ffffffff820337bb>] 
c [<ffffffff820337bb>] io_serial_in+0x6b/0x90 drivers/tty/serial/8250/8250_port.c:414
RSP: 0018:ffff8801c69df5d0  EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000005 RDI: ffffffff8615b278
RBP: ffff8801c69df5e0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 1ffff10038d3be9c R12: ffffffff8615b240
R13: 0000000000000020 R14: fffffbfff0c2b68f R15: fffffbfff0c2b651
FS:  00007f06fca6f7a0(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f06fc181a30 CR3: 00000001a68c4000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffffffff8615b240
c 000000000000270e
c ffff8801c69df630
c ffffffff820353ee
c
 ffff8801c69df668
c ffffffff8615b288
c ffffffff8615b47a
c ffffffff8615b240
c
 0000000000000034
c ffffffff82035530
c dffffc0000000000
c 0000000000000034
c
Call Trace:
 [<ffffffff820353ee>] serial_in drivers/tty/serial/8250/8250.h:111 [inline]
 [<ffffffff820353ee>] wait_for_xmitr+0x8e/0x1d0 drivers/tty/serial/8250/8250_port.c:1997
 [<ffffffff8203554f>] serial8250_console_putchar+0x1f/0x60 drivers/tty/serial/8250/8250_port.c:3100
 [<ffffffff8201d84c>] uart_console_write+0xac/0xe0 drivers/tty/serial/serial_core.c:1855
 [<ffffffff82040f60>] serial8250_console_write+0x2e0/0x850 drivers/tty/serial/8250/8250_port.c:3166
 [<ffffffff8202e38f>] univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:594
 [<ffffffff81265c85>] call_console_drivers.isra.20.constprop.29+0x1a5/0x350 kernel/printk/printk.c:1589
 [<ffffffff812688b5>] console_unlock+0x425/0xb20 kernel/printk/printk.c:2445
 [<ffffffff81269d05>] console_device+0x95/0xc0 kernel/printk/printk.c:2553
 [<ffffffff81ffc1d5>] tty_lookup_driver drivers/tty/tty_io.c:1986 [inline]
 [<ffffffff81ffc1d5>] tty_open_by_driver drivers/tty/tty_io.c:2031 [inline]
 [<ffffffff81ffc1d5>] tty_open+0x425/0xdf0 drivers/tty/tty_io.c:2108
 [<ffffffff8157a2cb>] chrdev_open+0x22b/0x4c0 fs/char_dev.c:392
 [<ffffffff81565497>] do_dentry_open+0x607/0xc60 fs/open.c:766
 [<ffffffff81568f45>] vfs_open+0x105/0x220 fs/open.c:879
 [<ffffffff8159f39c>] do_last fs/namei.c:3402 [inline]
 [<ffffffff8159f39c>] path_openat+0x5ac/0x2910 fs/namei.c:3525
 [<ffffffff815a4ef7>] do_filp_open+0x197/0x290 fs/namei.c:3560
 [<ffffffff81569a22>] do_sys_open+0x352/0x4c0 fs/open.c:1072
 [<ffffffff81569bbd>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff81569bbd>] SyS_open+0x2d/0x40 fs/open.c:1085
 [<ffffffff838aa045>] entry_SYSCALL_64_fastpath+0x23/0xc6
Code: 
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