Buffer I/O error on dev loop0, logical block 6, lost async page write
Buffer I/O error on dev loop0, logical block 7, lost async page write
Buffer I/O error on dev loop0, logical block 8, lost async page write
Buffer I/O error on dev loop0, logical block 9, lost async page write
IPVS: Creating netns size=2536 id=13
INFO: task syz-executor5:10410 blocked for more than 120 seconds.
      Not tainted 4.9.86-g00db063 #60
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D26448 10410   3871 0x20020006
 ffff8801ce2ab000 0000000000000000 ffff8801cc8e79c0 ffffffff84429880
 ffff8801db221b98 ffff8801cd85f370 ffffffff838a457b 0000000041b58ab3
 ffffffff84193a88 00ffffff8123c030 ffff8801db222468 ffff8801db222490
Call Trace:
 [<ffffffff838a5b1f>] schedule+0x7f/0x1b0 kernel/sched/core.c:3550
 [<ffffffff838b1c7c>] schedule_timeout+0x56c/0x10b0 kernel/time/timer.c:1768
 [<ffffffff838a3d2e>] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:5172
 [<ffffffff838a6f99>] io_schedule include/linux/sched.h:460 [inline]
 [<ffffffff838a6f99>] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582
 [<ffffffff838a6677>] __wait_on_bit+0x57/0x120 kernel/sched/wait.c:383
 [<ffffffff814325c4>] wait_on_page_bit+0xf4/0x140 mm/filemap.c:802
 [<ffffffff814327d1>] wait_on_page_writeback include/linux/pagemap.h:526 [inline]
 [<ffffffff814327d1>] __filemap_fdatawait_range+0x1c1/0x2b0 mm/filemap.c:453
 [<ffffffff814328e5>] filemap_fdatawait_range+0x25/0x50 mm/filemap.c:483
 [<ffffffff8143b515>] filemap_fdatawait mm/filemap.c:533 [inline]
 [<ffffffff8143b515>] filemap_write_and_wait+0xf5/0x120 mm/filemap.c:551
 [<ffffffff8162d850>] __sync_blockdev fs/block_dev.c:194 [inline]
 [<ffffffff8162d850>] sync_blockdev.part.28+0x50/0x70 fs/block_dev.c:203
 [<ffffffff8162de74>] sync_blockdev fs/block_dev.c:190 [inline]
 [<ffffffff8162de74>] __blkdev_put+0x184/0x7e0 fs/block_dev.c:1585
 [<ffffffff8162f2a5>] blkdev_put+0x85/0x550 fs/block_dev.c:1663
 [<ffffffff8162f7fb>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1670
 [<ffffffff815757cc>] __fput+0x28c/0x6e0 fs/file_table.c:208
 [<ffffffff81575ca5>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff81195855>] task_work_run+0x115/0x190 kernel/task_work.c:116
 [<ffffffff8113c2c7>] exit_task_work include/linux/task_work.h:21 [inline]
 [<ffffffff8113c2c7>] do_exit+0x7e7/0x2a40 kernel/exit.c:833
 [<ffffffff811429d8>] do_group_exit+0x108/0x320 kernel/exit.c:937
 [<ffffffff81165854>] get_signal+0x4d4/0x14e0 kernel/signal.c:2317
 [<ffffffff81052c87>] do_signal+0x87/0x19f0 arch/x86/kernel/signal.c:807
 [<ffffffff81003a31>] exit_to_usermode_loop+0xe1/0x120 arch/x86/entry/common.c:157
 [<ffffffff81007261>] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
 [<ffffffff81007261>] syscall_return_slowpath arch/x86/entry/common.c:260 [inline]
 [<ffffffff81007261>] do_syscall_32_irqs_on arch/x86/entry/common.c:331 [inline]
 [<ffffffff81007261>] do_fast_syscall_32+0x5c1/0x870 arch/x86/entry/common.c:387
 [<ffffffff838b6d10>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137

Showing all locks held in the system:
3 locks held by kworker/u4:2/35:
 #0:  ("writeback"){++++.+}, at: [<ffffffff811897b2>] work_static include/linux/workqueue.h:186 [inline]
 #0:  ("writeback"){++++.+}, at: [<ffffffff811897b2>] set_work_data kernel/workqueue.c:617 [inline]
 #0:  ("writeback"){++++.+}, at: [<ffffffff811897b2>] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0:  ("writeback"){++++.+}, at: [<ffffffff811897b2>] process_one_work+0x6f2/0x1610 kernel/workqueue.c:2085
 #1:  ((&(&wb->dwork)->work)){+.+.+.}, at: [<ffffffff811897ec>] process_one_work+0x72c/0x1610 kernel/workqueue.c:2089
 #2:  (&type->s_umount_key#22){.+.+..}, at: [<ffffffff81579ce0>] trylock_super+0x20/0x100 fs/super.c:393
2 locks held by khungtaskd/515:
 #0:  (rcu_read_lock){......}, at: [<ffffffff81373065>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff81373065>] watchdog+0x125/0xa70 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81238190>] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336
1 lock held by rsyslogd/3648:
 #0:  (&f->f_pos_lock){+.+.+.}, at: [<ffffffff815d3c2f>] __fdget_pos+0x9f/0xc0 fs/file.c:781
2 locks held by getty/3776:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff838b37f2>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+.+.}, at: [<ffffffff8200abe4>] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133
1 lock held by syz-executor5/10410:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8162ddac>] __blkdev_put+0xbc/0x7e0 fs/block_dev.c:1579
1 lock held by blkid/10600:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8162e5dc>] __blkdev_get+0x10c/0xd50 fs/block_dev.c:1268
1 lock held by syz-executor5/10768:
 #0:  (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8162e5dc>] __blkdev_get+0x10c/0xd50 fs/block_dev.c:1268

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

NMI backtrace for cpu 0
CPU: 0 PID: 515 Comm: khungtaskd Not tainted 4.9.86-g00db063 #60
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d84d7d00 ffffffff81d956f9 0000000000000000 0000000000000000
 0000000000000000 0000000000000001 ffffffff810bb190 ffff8801d84d7d38
 ffffffff81da081d 0000000000000000 0000000000000000 ffff8801cd5de418
Call Trace:
 [<ffffffff81d956f9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d956f9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81da081d>] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99
 [<ffffffff81da0957>] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60
 [<ffffffff810bb284>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81373630>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81373630>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81373630>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81373630>] watchdog+0x6f0/0xa70 kernel/hung_task.c:239
 [<ffffffff8119a7bd>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff838b57ac>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:374
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff838b4266