INFO: task syz-executor.0:23182 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D27680 23182 1856 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+0x559/0x1430 kernel/locking/mutex.c:893 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 loop_reread_partitions+0x72/0x80 drivers/block/loop.c:614 loop_clr_fd+0x828/0xac0 drivers/block/loop.c:1068 lo_ioctl+0x460/0x1a30 drivers/block/loop.c:1414 INFO: task syz-executor.4:23185 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D27744 23185 1859 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+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x183/0x300 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/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.4:23197 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29968 23197 1859 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+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 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/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.4:23203 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29496 23203 1859 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+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 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/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.3:23186 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28192 23186 1857 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+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 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/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.3:23199 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D30088 23199 1857 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+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 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/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.3:23204 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28320 23204 1857 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+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 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/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.3:23220 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29128 23220 1857 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+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 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/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.3:23224 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D30304 23224 1857 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+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 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/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.5:23193 blocked for more than 140 seconds. Not tainted 4.14.127+ #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D27744 23193 1851 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+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 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/0x510 arch/x86/entry/common.c:292 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [<0000000002bfb74f>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541 2 locks held by getty/1764: #0: (&tty->ldisc_sem){++++}, at: [<00000000c2fe1703>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c3ea5b75>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.0/23182: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000555b3cda>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.}, at: [<0000000034ba62e6>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 2 locks held by syz-executor.4/23185: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 #1: (&lo->lo_ctl_mutex#2){+.+.}, at: [<000000000bebc025>] loop_control_ioctl+0x183/0x300 drivers/block/loop.c:1996 1 lock held by syz-executor.4/23197: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.4/23203: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.3/23186: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.3/23199: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.3/23204: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.3/23220: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.3/23224: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.5/23193: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.5/23200: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.5/23205: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.5/23221: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 2 locks held by blkid/23190: #0: (&bdev->bd_mutex){+.+.}, at: [<000000005ed68e35>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<0000000021c06a98>] lo_open+0x19/0xb0 drivers/block/loop.c:1623 1 lock held by syz-executor.2/23194: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.2/23202: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 1 lock held by syz-executor.2/23206: #0: (loop_index_mutex){+.+.}, at: [<00000000f7219abe>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.127+ #9 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x10e lib/dump_stack.c:53 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff9b65dc83