INFO: task syz-executor.4:19928 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D27360 19928 5598 0x00000006 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_release+0x1b/0x1a0 drivers/block/loop.c:1667 __blkdev_put+0x518/0x6d0 fs/block_dev.c:1791 blkdev_close+0x86/0xb0 fs/block_dev.c:1863 __fput+0x25e/0x710 fs/file_table.c:210 task_work_run+0x125/0x1a0 kernel/task_work.c:113 get_signal+0x189a/0x1cc0 kernel/signal.c:2233 do_signal+0x96/0x15d0 arch/x86/kernel/signal.c:814 exit_to_usermode_loop+0x11d/0x160 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x3a3/0x520 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a087 RSP: 002b:00007f54f254c9f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00007f54f254d6d4 RCX: 000000000045a087 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000005 RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000000c R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000004 R13: 0000000000000000 R14: 0000000000000005 R15: 0000000000000001 INFO: task syz-executor.1:19923 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28624 19923 19634 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_put+0x27/0x4c0 fs/block_dev.c:1814 blkdev_close+0x86/0xb0 fs/block_dev.c:1863 __fput+0x25e/0x710 fs/file_table.c:210 task_work_run+0x125/0x1a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x3a3/0x520 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x413db1 RSP: 002b:00007ffeb4ec1420 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000413db1 RDX: 0000000000000000 RSI: ffffffff81e37a06 RDI: 0000000000000007 RBP: 0000000000000001 R08: ffffffff811f66f4 R09: 00000000548cda20 R10: 00007ffeb4ec1500 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000761758 R15: 000000000075bfd4 INFO: task syz-executor.1:19933 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D26960 19933 19634 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_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 __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: 0033:0x45a219 RSP: 002b:00007f1faaa47c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 000000000045a219 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1faaa486d4 R13: 00000000004c3c18 R14: 00000000004d7f90 R15: 00000000ffffffff INFO: task syz-executor.5:19935 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D26496 19935 6972 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: 0033:0x45a087 RSP: 002b:00007f00604db9f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f00604dc6d4 RCX: 000000000045a087 RDX: 00007f00604dbab0 RSI: 0000000000004c04 RDI: 0000000000000009 RBP: 000000000075bf20 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000008 R13: 0000000000000008 R14: 0000000000000009 R15: 00000000ffffffff INFO: task syz-executor.5:19970 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28552 19970 6972 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: 0033:0x413fb1 RSP: 002b:00007f00604999f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007f006049a6d4 RCX: 0000000000413fb1 RDX: 00007f0060499baa RSI: 0000000000000002 RDI: 00007f0060499ba0 RBP: 000000000075c070 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000293 R12: 0000000000000009 R13: 0000000000000009 R14: 00000000004e1de8 R15: 00000000ffffffff INFO: task syz-executor.0:19943 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28624 19943 10293 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_put+0x27/0x4c0 fs/block_dev.c:1814 blkdev_close+0x86/0xb0 fs/block_dev.c:1863 __fput+0x25e/0x710 fs/file_table.c:210 task_work_run+0x125/0x1a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x3a3/0x520 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x413db1 RSP: 002b:00007ffcf64ee1a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000413db1 RDX: 0000000000000000 RSI: 0000000000001a1c RDI: 0000000000000007 RBP: 0000000000000001 R08: 00000000548cda1c R09: 00000000548cda20 R10: 00007ffcf64ee280 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000762720 R15: 000000000075c07c INFO: task syz-executor.0:19944 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29072 19944 10293 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: 0033:0x45a087 RSP: 002b:00007f0127caa9f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f0127cab6d4 RCX: 000000000045a087 RDX: 00007f0127caaab0 RSI: 0000000000004c04 RDI: 0000000000000004 RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000003 R13: 0000000000000003 R14: 0000000000000004 R15: 00000000ffffffff INFO: task syz-executor.0:19954 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29088 19954 10293 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:1997 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: 0033:0x45a219 RSP: 002b:00007f0127c89c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a219 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 000000000000000a RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0127c8a6d4 R13: 00000000004c3c55 R14: 00000000004d7fd8 R15: 00000000ffffffff INFO: task syz-executor.3:19961 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28464 19961 5181 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: 0033:0x45a087 RSP: 002b:00007fdb945d79f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fdb945d86d4 RCX: 000000000045a087 RDX: 00007fdb945d7ab0 RSI: 0000000000004c04 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000004 R13: 0000000000000004 R14: 0000000000000005 R15: 00000000ffffffff INFO: task syz-executor.3:19966 blocked for more than 140 seconds. Not tainted 4.14.151+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29120 19966 5181 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: 0033:0x413fb1 RSP: 002b:00007fdb945b67a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000413fb1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fdb945b6850 RBP: 000000000075bfc8 R08: 000000000000000f R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00007fdb945b76d4 R13: 00000000004c9d95 R14: 00000000004e1b18 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [<000000006bdc09aa>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544 2 locks held by getty/1762: #0: (&tty->ldisc_sem){++++}, at: [<00000000c17c6ece>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000ae91b1ec>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.4/19928: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000027725b26>] __blkdev_put+0xb1/0x6d0 fs/block_dev.c:1778 #1: (loop_index_mutex){+.+.}, at: [<0000000080dd4e0e>] lo_release+0x1b/0x1a0 drivers/block/loop.c:1667 1 lock held by syz-executor.1/19923: #0: (&bdev->bd_mutex){+.+.}, at: [<000000003daba937>] blkdev_put+0x27/0x4c0 fs/block_dev.c:1814 1 lock held by syz-executor.1/19933: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<0000000042914a96>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 2 locks held by syz-executor.5/19935: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<0000000042914a96>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.}, at: [<0000000020c388aa>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 1 lock held by syz-executor.5/19970: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000df36961f>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 1 lock held by syz-executor.0/19943: #0: (&bdev->bd_mutex){+.+.}, at: [<000000003daba937>] blkdev_put+0x27/0x4c0 fs/block_dev.c:1814 2 locks held by syz-executor.0/19944: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<0000000042914a96>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.}, at: [<0000000020c388aa>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 2 locks held by syz-executor.0/19954: #0: (loop_index_mutex){+.+.}, at: [<00000000499aea3b>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1983 #1: (&lo->lo_ctl_mutex#2){+.+.}, at: [<00000000dddd7baa>] loop_control_ioctl+0x183/0x310 drivers/block/loop.c:1997 2 locks held by syz-executor.3/19961: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<0000000042914a96>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.}, at: [<0000000020c388aa>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 1 lock held by syz-executor.3/19966: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000df36961f>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 1 lock held by syz-executor.3/19969: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000df36961f>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 1 lock held by syz-executor.3/19973: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000df36961f>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 2 locks held by syz-executor.2/19960: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000df36961f>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000adc08c74>] lo_open+0x19/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.2/19965: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000df36961f>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000adc08c74>] lo_open+0x19/0xb0 drivers/block/loop.c:1624 1 lock held by blkid/19952: #0: (&bdev->bd_mutex){+.+.}, at: [<000000003daba937>] blkdev_put+0x27/0x4c0 fs/block_dev.c:1814 2 locks held by blkid/19955: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000027725b26>] __blkdev_put+0xb1/0x6d0 fs/block_dev.c:1778 #1: (loop_index_mutex){+.+.}, at: [<0000000080dd4e0e>] lo_release+0x1b/0x1a0 drivers/block/loop.c:1667 1 lock held by blkid/19956: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000df36961f>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 1 lock held by blkid/19957: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<0000000042914a96>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 2 locks held by blkid/19959: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000df36961f>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000adc08c74>] lo_open+0x19/0xb0 drivers/block/loop.c:1624 2 locks held by blkid/19964: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000df36961f>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000adc08c74>] lo_open+0x19/0xb0 drivers/block/loop.c:1624 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.151+ #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 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff984a4e43