blk_update_request: I/O error, dev loop7, sector 0
Buffer I/O error on dev loop7p1, logical block 0, async page read
blk_update_request: I/O error, dev loop7, sector 0
Buffer I/O error on dev loop7p1, logical block 0, async page read
Buffer I/O error on dev loop7p1, logical block 0, async page read
INFO: task syz-executor5:7844 blocked for more than 140 seconds.
      Not tainted 4.9.119-g9dc978d #23
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5   D29016  7844   3831 0x00000004
 ffff8801cc853000 ffff8801d3e74a80 ffff8801d3e74a80 ffff8801cd303000
 ffff8801db221c18 ffff8801cce676c8 ffffffff839ebdcd dffffc0000000000
 ffff8801cbfa03d0 ffff8801cce67688 00ff8801cc8538c0 ffff8801db2224e8
Call Trace:
 [<ffffffff839ed3cf>] schedule+0x7f/0x1b0 kernel/sched/core.c:3553
 [<ffffffff815c8102>] d_wait_lookup fs/dcache.c:2455 [inline]
 [<ffffffff815c8102>] d_alloc_parallel+0xeb2/0x17c0 fs/dcache.c:2537
 [<ffffffff8159b3da>] lookup_open+0x4ba/0x1930 fs/namei.c:3134
 [<ffffffff815a5ad3>] do_last fs/namei.c:3315 [inline]
 [<ffffffff815a5ad3>] path_openat+0x1803/0x3590 fs/namei.c:3534
 [<ffffffff815abb27>] do_filp_open+0x197/0x270 fs/namei.c:3568
 [<ffffffff8156e2fd>] do_sys_open+0x30d/0x5c0 fs/open.c:1072
 [<ffffffff8156e5dd>] SYSC_open fs/open.c:1090 [inline]
 [<ffffffff8156e5dd>] SyS_open+0x2d/0x40 fs/open.c:1085
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fccd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:
2 locks held by khungtaskd/519:
 #0:  (rcu_read_lock){......}, at: [<ffffffff813667bc>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
 #0:  (rcu_read_lock){......}, at: [<ffffffff813667bc>] watchdog+0x11c/0xa20 kernel/hung_task.c:239
 #1:  (tasklist_lock){.+.+..}, at: [<ffffffff81426027>] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336
2 locks held by getty/3724:
 #0:  (&tty->ldisc_sem){++++++}, at: [<ffffffff839fae72>] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367
 #1:  (&ldata->atomic_read_lock){+.+...}, at: [<ffffffff821208d2>] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor5/7743:
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815a5aac>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815a5aac>] do_last fs/namei.c:3314 [inline]
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815a5aac>] path_openat+0x17dc/0x3590 fs/namei.c:3534
1 lock held by syz-executor5/7844:
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815a5aac>] inode_lock_shared include/linux/fs.h:776 [inline]
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815a5aac>] do_last fs/namei.c:3314 [inline]
 #0:  (&sb->s_type->i_mutex_key#22){++++++}, at: [<ffffffff815a5aac>] path_openat+0x17dc/0x3590 fs/namei.c:3534

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

NMI backtrace for cpu 1
CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.119-g9dc978d #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d84c7d08 ffffffff81eb4be9 0000000000000000 0000000000000001
 0000000000000001 0000000000000001 ffffffff810b9bd0 ffff8801d84c7d40
 ffffffff81ebfee7 0000000000000001 0000000000000000 0000000000000003
Call Trace:
 [<ffffffff81eb4be9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb4be9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81ebfee7>] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99
 [<ffffffff81ebfe7a>] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60
 [<ffffffff810b9cd4>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37
 [<ffffffff81366d54>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline]
 [<ffffffff81366d54>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff81366d54>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff81366d54>] watchdog+0x6b4/0xa20 kernel/hung_task.c:239
 [<ffffffff8119d0ed>] kthread+0x26d/0x300 kernel/kthread.c:211
 [<ffffffff839fce9c>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff839fb8d6