INFO: task syz-executor.2:7182 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D25168 7182 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x145/0x1120 fs/block_dev.c:1457 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73e/0xeb0 fs/open.c:758 vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_open fs/open.c:1083 [inline] SyS_open+0x2d/0x40 fs/open.c:1078 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x412270 RSP: 002b:00007ffce3cd1958 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000000000002ac2e RCX: 0000000000412270 RDX: 00007ffce3cd19ea RSI: 0000000000000002 RDI: 00007ffce3cd19e0 RBP: 000000000000024f R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffce3cd1990 R14: 000000000002abcf R15: 00007ffce3cd19a0 INFO: task syz-executor.5:7183 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D24992 7183 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __lo_release drivers/block/loop.c:1644 [inline] lo_release+0x84/0x1b0 drivers/block/loop.c:1668 __blkdev_put+0x436/0x7f0 fs/block_dev.c:1791 blkdev_put+0x88/0x510 fs/block_dev.c:1856 blkdev_close+0x8b/0xb0 fs/block_dev.c:1863 __fput+0x277/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x119/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:267 [inline] do_syscall_64+0x4a9/0x630 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x412090 RSP: 002b:00007ffc0cc71ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000412090 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003 RBP: 00000000000002fb R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc0cc71d20 R14: 000000000002ab87 R15: 00007ffc0cc71d30 INFO: task syz-executor.4:7185 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D24920 7185 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_open+0x1d/0xb0 drivers/block/loop.c:1624 __blkdev_get+0x2c9/0x1120 fs/block_dev.c:1472 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73e/0xeb0 fs/open.c:758 vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_open fs/open.c:1083 [inline] SyS_open+0x2d/0x40 fs/open.c:1078 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x412270 RSP: 002b:00007ffcb72492d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000000000002ac86 RCX: 0000000000412270 RDX: 00007ffcb724936a RSI: 0000000000000002 RDI: 00007ffcb7249360 RBP: 00000000000002ad R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcb7249310 R14: 000000000002ab8c R15: 00007ffcb7249320 INFO: task syz-executor.0:7186 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D25168 7186 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_open+0x1d/0xb0 drivers/block/loop.c:1624 __blkdev_get+0x2c9/0x1120 fs/block_dev.c:1472 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73e/0xeb0 fs/open.c:758 vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_open fs/open.c:1083 [inline] SyS_open+0x2d/0x40 fs/open.c:1078 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x412270 RSP: 002b:00007fff19deda78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000000000002ac99 RCX: 0000000000412270 RDX: 00007fff19dedb0a RSI: 0000000000000002 RDI: 00007fff19dedb00 RBP: 00000000000002c9 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff19dedab0 R14: 000000000002ab83 R15: 00007fff19dedac0 INFO: task syz-executor.1:7187 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D24992 7187 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_open+0x1d/0xb0 drivers/block/loop.c:1624 __blkdev_get+0x2c9/0x1120 fs/block_dev.c:1472 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73e/0xeb0 fs/open.c:758 vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_open fs/open.c:1083 [inline] SyS_open+0x2d/0x40 fs/open.c:1078 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x412270 RSP: 002b:00007ffe6d2e66a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 000000000002aebf RCX: 0000000000412270 RDX: 00007ffe6d2e673a RSI: 0000000000000002 RDI: 00007ffe6d2e6730 RBP: 000000000000019d R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe6d2e66e0 R14: 000000000002ab92 R15: 00007ffe6d2e66f0 INFO: task syz-executor.3:12707 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28944 12707 7184 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 blkdev_reread_part+0x1f/0x40 block/ioctl.c:192 loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:615 loop_set_status+0xc28/0x1200 drivers/block/loop.c:1184 loop_set_status64+0xa6/0xf0 drivers/block/loop.c:1302 lo_ioctl+0x5c1/0x1c70 drivers/block/loop.c:1432 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x983/0x1880 block/ioctl.c:594 block_ioctl+0xde/0x120 fs/block_dev.c:1881 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7b9/0x1070 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x458167 RSP: 002b:00007f34b1eb39f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f34b1eb46d4 RCX: 0000000000458167 RDX: 00007f34b1eb3ab0 RSI: 0000000000004c04 RDI: 0000000000000006 RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000005 R13: 0000000000000005 R14: 0000000000000006 R15: 00000000ffffffff INFO: task blkid:12706 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D28368 12706 7147 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_open+0x1d/0xb0 drivers/block/loop.c:1624 __blkdev_get+0x2c9/0x1120 fs/block_dev.c:1472 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73e/0xeb0 fs/open.c:758 vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_open fs/open.c:1083 [inline] SyS_open+0x2d/0x40 fs/open.c:1078 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7f05f02d8120 RSP: 002b:00007fff5ebc0908 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f05f02d8120 RDX: 00007fff5ebc1f34 RSI: 0000000000000000 RDI: 00007fff5ebc1f34 RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001e7f030 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005 INFO: task blkid:12712 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D28632 12712 7146 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_open+0x1d/0xb0 drivers/block/loop.c:1624 __blkdev_get+0xab1/0x1120 fs/block_dev.c:1537 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73e/0xeb0 fs/open.c:758 vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_open fs/open.c:1083 [inline] SyS_open+0x2d/0x40 fs/open.c:1078 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7fc02fc62120 RSP: 002b:00007ffc573eaed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc02fc62120 RDX: 00007ffc573ecf41 RSI: 0000000000000000 RDI: 00007ffc573ecf41 RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001a5a030 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005 INFO: task blkid:12713 blocked for more than 140 seconds. Not tainted 4.14.111 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D29040 12713 7308 0x00000004 Call Trace: context_switch kernel/sched/core.c:2807 [inline] __schedule+0x7be/0x1cf0 kernel/sched/core.c:3383 schedule+0x92/0x1c0 kernel/sched/core.c:3427 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x145/0x1120 fs/block_dev.c:1457 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770 do_dentry_open+0x73e/0xeb0 fs/open.c:758 vfs_open+0x105/0x230 fs/open.c:872 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1065 SYSC_open fs/open.c:1083 [inline] SyS_open+0x2d/0x40 fs/open.c:1078 do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7f68d593a120 RSP: 002b:00007ffc2d563a88 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f68d593a120 RDX: 00007ffc2d565f34 RSI: 0000000000000000 RDI: 00007ffc2d565f34 RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000011bf030 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005 Showing all locks held in the system: 1 lock held by khungtaskd/1009: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544 2 locks held by getty/7138: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7139: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7140: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7141: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7142: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7143: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 2 locks held by getty/7144: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.2/7182: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457 3 locks held by syz-executor.5/7183: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_put+0xa6/0x7f0 fs/block_dev.c:1778 #1: (loop_index_mutex){+.+.}, at: [] lo_release+0x1e/0x1b0 drivers/block/loop.c:1667 #2: (loop_ctl_mutex#2){+.+.}, at: [] __lo_release drivers/block/loop.c:1644 [inline] #2: (loop_ctl_mutex#2){+.+.}, at: [] lo_release+0x84/0x1b0 drivers/block/loop.c:1668 2 locks held by syz-executor.4/7185: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x1d/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.0/7186: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x1d/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.1/7187: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x1d/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.3/12707: #0: (loop_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x87/0x1c70 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x1f/0x40 block/ioctl.c:192 2 locks held by blkid/12706: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x1d/0xb0 drivers/block/loop.c:1624 2 locks held by blkid/12712: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x1d/0xb0 drivers/block/loop.c:1624 1 lock held by blkid/12713: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1009 Comm: khungtaskd Not tainted 4.14.111 #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x138/0x19c lib/dump_stack.c:53 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:194 [inline] watchdog+0x5d8/0xb80 kernel/hung_task.c:250 kthread+0x31c/0x430 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff861a94c2