device loop0 blocksize: 4096
isofs_fill_super: root inode is not a directory. Corrupted media?
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
INFO: task syz-executor0:11045 blocked for more than 140 seconds.
      Not tainted 4.20.0-rc4+ #134
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0   D19736 11045   6181 0x80000006
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
Call Trace:
 context_switch kernel/sched/core.c:2831 [inline]
 __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 schedule+0xfe/0x460 kernel/sched/core.c:3516
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 __rwsem_down_write_failed_common+0xc9a/0x15e0 kernel/locking/rwsem-xadd.c:577
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:606
__find_get_block_slow() failed. block=1, b_blocknr=8
 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117
 __down_write arch/x86/include/asm/rwsem.h:142 [inline]
 down_write+0xa5/0x130 kernel/locking/rwsem.c:72
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 deactivate_super+0x2b3/0x320 fs/super.c:359
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
 cleanup_mnt+0xbf/0x160 fs/namespace.c:1098
device loop0 blocksize: 4096
 __cleanup_mnt+0x16/0x20 fs/namespace.c:1105
__find_get_block_slow() failed. block=1, b_blocknr=8
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x1ad6/0x26d0 kernel/exit.c:867
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 do_group_exit+0x177/0x440 kernel/exit.c:970
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
 get_signal+0x8b0/0x1980 kernel/signal.c:2517
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
 exit_to_usermode_loop+0x2e5/0x380 arch/x86/entry/common.c:162
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
RIP: 0033:0x457569
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
Code: Bad RIP value.
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
RSP: 002b:00007f6e7e480cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
RAX: fffffffffffffe00 RBX: 000000000072c048 RCX: 0000000000457569
__find_get_block_slow() failed. block=1, b_blocknr=8
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000072c048
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000072c04c
__find_get_block_slow() failed. block=1, b_blocknr=8
R13: 00007ffdc954f94f R14: 00007f6e7e4819c0 R15: 0000000000000002
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8

Showing all locks held in the system:
b_state=0x00000029, b_size=512
2 locks held by kworker/0:1/12:
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 #1: 0000000082fed078 ((work_completion)(&ns->proc_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128
6 locks held by kworker/u4:1/21:
1 lock held by khungtaskd/1020:
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 00000000a9c13944 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379
b_state=0x00000029, b_size=512
2 locks held by kworker/1:2/2938:
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124
 #1: 00000000421a18f9 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
1 lock held by rsyslogd/6015:
b_state=0x00000029, b_size=512
2 locks held by getty/6138:
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 000000008dfabb11 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #1: 00000000532ea63f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
2 locks held by getty/6139:
b_state=0x00000029, b_size=512
 #0: 000000005cd84127 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
device loop0 blocksize: 4096
 #1: 000000008696b96d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
__find_get_block_slow() failed. block=1, b_blocknr=8
2 locks held by getty/6140:
b_state=0x00000029, b_size=512
 #0: 000000001e0997f4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #1: 00000000cf5dc272 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
b_state=0x00000029, b_size=512
2 locks held by getty/6141:
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 000000000cc2bb18 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #1: 00000000ec0f7389 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
2 locks held by getty/6142:
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 #0: 0000000069664cd7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
__find_get_block_slow() failed. block=1, b_blocknr=8
 #1: 0000000064e715b9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
b_state=0x00000029, b_size=512
2 locks held by getty/6143:
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 000000001ee7f73d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
b_state=0x00000029, b_size=512
 #1: 00000000fd1e0d80 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
2 locks held by getty/6144:
device loop0 blocksize: 4096
 #0: 000000008a050b31 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
 #1: 000000005d966908 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
__find_get_block_slow() failed. block=1, b_blocknr=8
2 locks held by kworker/0:3/6304:
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124
b_state=0x00000029, b_size=512
 #1: 00000000114192dc ((work_completion)(&map->work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
1 lock held by syz-executor0/11045:
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 0000000035538f05 (&type->s_umount_key#71){++++}, at: deactivate_super+0x2b3/0x320 fs/super.c:359
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
2 locks held by syz-executor4/13590:
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 00000000d1c8f7d5 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x13c0 fs/block_dev.c:1466
b_state=0x00000029, b_size=512
 #1: 000000007f9f752c (loop_index_mutex){+.+.}, at: lo_open+0x1b/0xb0 drivers/block/loop.c:1630
device loop0 blocksize: 4096
2 locks held by kworker/0:0/15366:
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
 #1: 0000000051e41c85 ((work_completion)(&ns->proc_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128
__find_get_block_slow() failed. block=1, b_blocknr=8
2 locks held by kworker/0:4/15368:
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124
 #1: 00000000e1a14453 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
1 lock held by syz-executor5/21143:
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 00000000cc89dd1e (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x13c0 fs/block_dev.c:1466
b_state=0x00000029, b_size=512
2 locks held by syz-executor1/21437:
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 000000008eaa83db (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x13c0 fs/block_dev.c:1466
b_state=0x00000029, b_size=512
 #1: 000000007f9f752c (loop_index_mutex){+.+.}, at: lo_open+0x1b/0xb0 drivers/block/loop.c:1630
device loop0 blocksize: 4096
1 lock held by syz-executor0/21490:
__find_get_block_slow() failed. block=1, b_blocknr=8
 #0: 00000000e9810d05 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x13c0 fs/block_dev.c:1466
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
3 locks held by blkid/23720:
b_state=0x00000029, b_size=512
 #0: 00000000cc89dd1e (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0xc2/0x830 fs/block_dev.c:1783
device loop0 blocksize: 4096
 #1: 000000007f9f752c (loop_index_mutex){+.+.}, at: lo_release+0x1f/0x1f0 drivers/block/loop.c:1673
__find_get_block_slow() failed. block=1, b_blocknr=8
 #2: 00000000c984dd91 (&lo->lo_ctl_mutex#2){+.+.}, at: __lo_release drivers/block/loop.c:1650 [inline]
 #2: 00000000c984dd91 (&lo->lo_ctl_mutex#2){+.+.}, at: lo_release+0xa3/0x1f0 drivers/block/loop.c:1674
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
2 locks held by blkid/23729:
b_state=0x00000029, b_size=512
 #0: 00000000e9810d05 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x19b/0x13c0 fs/block_dev.c:1466
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 #1: 000000007f9f752c (loop_index_mutex){+.+.}, at: lo_open+0x1b/0xb0 drivers/block/loop.c:1630
b_state=0x00000029, b_size=512
2 locks held by kworker/0:5/23752:
device loop0 blocksize: 4096
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:209 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000b9298c45 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb43/0x1c40 kernel/workqueue.c:2124
__find_get_block_slow() failed. block=1, b_blocknr=8
 #1: 000000004d472dfc ((work_completion)(&ns->proc_work)){+.+.}, at: process_one_work+0xb9a/0x1c40 kernel/workqueue.c:2128
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8

b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
kobject: 'loop5' (000000007c065642): kobject_uevent_env
b_state=0x00000029, b_size=512
kobject: 'loop5' (000000007c065642): fill_kobj_path: path = '/devices/virtual/block/loop5'
device loop0 blocksize: 4096
=============================================

__find_get_block_slow() failed. block=1, b_blocknr=8
NMI backtrace for cpu 0
b_state=0x00000029, b_size=512
CPU: 0 PID: 1020 Comm: khungtaskd Not tainted 4.20.0-rc4+ #134
device loop0 blocksize: 4096
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1e8/0x22a lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
device loop0 blocksize: 4096
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline]
 watchdog+0xb51/0x1060 kernel/hung_task.c:289
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
b_state=0x00000029, b_size=512
device loop0 blocksize: 4096
__find_get_block_slow() failed. block=1, b_blocknr=8
 kthread+0x35a/0x440 kernel/kthread.c:246
b_state=0x00000029, b_size=512
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 0 to CPUs 1:
device loop0 blocksize: 4096
NMI backtrace for cpu 1
CPU: 1 PID: 21 Comm: kworker/u4:1 Not tainted 4.20.0-rc4+ #134
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:__read_once_size include/linux/compiler.h:182 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:69 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:101
Code: 5d c3 66 90 55 48 89 e5 48 8b 75 08 65 48 8b 04 25 40 ee 01 00 65 8b 15 b8 62 82 7e 81 e2 00 01 1f 00 75 2b 8b 90 d8 12 00 00 <83> fa 02 75 20 48 8b 88 e0 12 00 00 8b 80 dc 12 00 00 48 8b 11 48
RSP: 0018:ffff8881d9465d40 EFLAGS: 00000046
RAX: ffff8881d945a580 RBX: 0000000000000001 RCX: ffffffff81653796
RDX: 0000000000000000 RSI: ffffffff816537a3 RDI: 0000000000000001
RBP: ffff8881d9465d40 R08: ffff8881d945a580 R09: ffffed103b28cbab
R10: ffffed103b28cbab R11: 0000000000000003 R12: 0000000000000000
R13: ffffffff8b0b6360 R14: 0000000000000024 R15: 000000ca7f9cd893
FS:  0000000000000000(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe7e1b9aa0 CR3: 00000001c4fbe000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 print_time kernel/printk/printk.c:1223 [inline]
 print_prefix+0x203/0x3f0 kernel/printk/printk.c:1251
 msg_print_text+0xcc/0x1d0 kernel/printk/printk.c:1278
 console_unlock+0x4e6/0x1190 kernel/printk/printk.c:2388
 vprintk_emit+0x391/0x990 kernel/printk/printk.c:1922
 vprintk_default+0x28/0x30 kernel/printk/printk.c:1964
 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
 printk+0xa7/0xcf kernel/printk/printk.c:1997
 __find_get_block_slow fs/buffer.c:237 [inline]
 __find_get_block.cold.57+0xd8/0xff fs/buffer.c:1294
 __getblk_slow fs/buffer.c:1039 [inline]
 __getblk_gfp+0x2b3/0xd50 fs/buffer.c:1320
 __bread_gfp+0x2d/0x310 fs/buffer.c:1354
 sb_bread include/linux/buffer_head.h:307 [inline]
 __fat_write_inode+0x347/0xb60 fs/fat/inode.c:859
 fat_write_inode+0x97/0x180 fs/fat/inode.c:908
 write_inode fs/fs-writeback.c:1176 [inline]
 __writeback_single_inode+0xf56/0x1660 fs/fs-writeback.c:1375
 writeback_sb_inodes+0x71f/0x1210 fs/fs-writeback.c:1580
 __writeback_inodes_wb+0x1b9/0x340 fs/fs-writeback.c:1649
 wb_writeback+0xa73/0xfc0 fs/fs-writeback.c:1758
 wb_check_old_data_flush fs/fs-writeback.c:1860 [inline]
 wb_do_writeback fs/fs-writeback.c:1913 [inline]
 wb_workfn+0x1008/0x1790 fs/fs-writeback.c:1942
 process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
 worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
 kthread+0x35a/0x440 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352