audit: type=1400 audit(1568849111.248:8): avc:  denied  { map } for  pid=1889 comm="syz-executor015" path="/root/syz-executor015546883" dev="sda1" ino=15946 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
INFO: task syz-executor015:1891 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor015 D29168  1891   1889 0x00000000
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4013e0
RSP: 002b:00007fff99fccdc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000782 RCX: 00000000004013e0
RDX: 00007fff99fcce8a RSI: 0000000000000002 RDI: 00007fff99fcce80
RBP: 00000000000a1905 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000402680
R13: 0000000000402710 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor015:1893 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor015 D28512  1893   1889 0x00000000
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4013e0
RSP: 002b:00007fff99fccdc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000783 RCX: 00000000004013e0
RDX: 00007fff99fcce8a RSI: 0000000000000002 RDI: 00007fff99fcce80
RBP: 00000000000a1905 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000402680
R13: 0000000000402710 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor015:1933 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor015 D28176  1933   1895 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7f/0x90 drivers/block/loop.c:614
 loop_set_status+0xbff/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa5/0x100 drivers/block/loop.c:1301
 lo_ioctl+0xd1/0x1a30 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x8d0/0x1870 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441877
RSP: 002b:00007fff99fccb78 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441877
RDX: 00007fff99fccc10 RSI: 0000000000004c04 RDI: 0000000000000005
RBP: 0000000000000004 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000402680
R13: 0000000000000005 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor015:1934 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor015 D28448  1934   1890 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7f/0x90 drivers/block/loop.c:614
 loop_set_status+0xbff/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa5/0x100 drivers/block/loop.c:1301
 lo_ioctl+0xd1/0x1a30 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x8d0/0x1870 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441877
RSP: 002b:00007fff99fccb78 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441877
RDX: 00007fff99fccc10 RSI: 0000000000004c04 RDI: 0000000000000005
RBP: 0000000000000004 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000402680
R13: 0000000000000005 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor015:1937 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor015 D28224  1937   1892 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7f/0x90 drivers/block/loop.c:614
 loop_set_status+0xbff/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa5/0x100 drivers/block/loop.c:1301
 lo_ioctl+0xd1/0x1a30 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x8d0/0x1870 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441877
RSP: 002b:00007fff99fccb78 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441877
RDX: 00007fff99fccc10 RSI: 0000000000004c04 RDI: 0000000000000005
RBP: 0000000000000004 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000402680
R13: 0000000000000005 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor015:1944 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor015 D28624  1944   1894 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 loop_control_ioctl+0x183/0x310 drivers/block/loop.c:1996
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x441969
RSP: 002b:00007fff99fccdb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441969
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000003
RBP: 00000000000a177e R08: 0000000000402710 R09: 0000000000402710
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000402680
R13: 0000000000402710 R14: 0000000000000000 R15: 0000000000000000
INFO: task blkid:1946 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28752  1946   1904 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fc55dae4120
RSP: 002b:00007ffe29aeaa28 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc55dae4120
RDX: 00007ffe29aecf41 RSI: 0000000000000000 RDI: 00007ffe29aecf41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000092f030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task blkid:1947 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28800  1947   1910 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x963/0xf90 fs/block_dev.c:1537
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f8e7cc0b120
RSP: 002b:00007ffdb171e0e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8e7cc0b120
RDX: 00007ffdb171ef41 RSI: 0000000000000000 RDI: 00007ffdb171ef41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000002441030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task blkid:1948 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D27808  1948   1901 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 lo_open+0x19/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0x963/0xf90 fs/block_dev.c:1537
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f2e916c4120
RSP: 002b:00007fff794033e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2e916c4120
RDX: 00007fff79404f41 RSI: 0000000000000000 RDI: 00007fff79404f41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000002155030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task blkid:1949 blocked for more than 140 seconds.
      Not tainted 4.14.144+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28352  1949   1903 0x00000004
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x595/0x13e0 kernel/locking/mutex.c:893
 __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612
 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770
 do_dentry_open+0x44e/0xe20 fs/open.c:789
 vfs_open+0x105/0x230 fs/open.c:903
 do_last fs/namei.c:3539 [inline]
 path_openat+0xb6c/0x2be0 fs/namei.c:3681
 do_filp_open+0x1a1/0x280 fs/namei.c:3715
 do_sys_open+0x2ca/0x590 fs/open.c:1096
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f5f53045120
RSP: 002b:00007ffd5403cf58 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5f53045120
RDX: 00007ffd5403df41 RSI: 0000000000000000 RDI: 00007ffd5403df41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000e12030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005

Showing all locks held in the system:
1 lock held by khungtaskd/23:
 #0:  (tasklist_lock){.+.+}, at: [<        (ptrval)>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541
2 locks held by getty/1757:
 #0:  (&tty->ldisc_sem){++++}, at: [<        (ptrval)>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<        (ptrval)>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
2 locks held by syz-executor015/1891:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_open+0x19/0xb0 drivers/block/loop.c:1623
2 locks held by syz-executor015/1893:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_open+0x19/0xb0 drivers/block/loop.c:1623
2 locks held by syz-executor015/1933:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
2 locks held by syz-executor015/1934:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
2 locks held by syz-executor015/1937:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<        (ptrval)>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192
2 locks held by syz-executor015/1944:
 #0:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982
 #1:  (&lo->lo_ctl_mutex#2){+.+.}, at: [<        (ptrval)>] loop_control_ioctl+0x183/0x310 drivers/block/loop.c:1996
2 locks held by blkid/1946:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_open+0x19/0xb0 drivers/block/loop.c:1623
2 locks held by blkid/1947:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_open+0x19/0xb0 drivers/block/loop.c:1623
2 locks held by blkid/1948:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_open+0x19/0xb0 drivers/block/loop.c:1623
1 lock held by blkid/1949:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
1 lock held by blkid/1951:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
2 locks held by blkid/1952:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<        (ptrval)>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<        (ptrval)>] lo_open+0x19/0xb0 drivers/block/loop.c:1623

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

NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.144+ #0
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xca/0x134 lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x119/0x147 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x629/0xbe0 kernel/hung_task.c:274
 kthread+0x31f/0x430 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff89a9b993