INFO: task syz-executor.0:18607 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29952 18607 1838 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 INFO: task syz-executor.5:18600 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D27968 18600 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+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 INFO: task syz-executor.5:18611 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D29616 18611 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+0x595/0x13e0 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x310 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/0x520 arch/x86/entry/common.c:292 INFO: task syz-executor.5:18616 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D29920 18616 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+0x595/0x13e0 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x310 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/0x520 arch/x86/entry/common.c:292 INFO: task syz-executor.5:18621 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28592 18621 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+0x595/0x13e0 kernel/locking/mutex.c:893 loop_control_ioctl+0x71/0x310 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/0x520 arch/x86/entry/common.c:292 INFO: task syz-executor.3:18608 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28704 18608 1852 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+0x71/0x310 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/0x520 arch/x86/entry/common.c:292 INFO: task syz-executor.3:18614 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29952 18614 1852 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+0x71/0x310 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/0x520 arch/x86/entry/common.c:292 INFO: task syz-executor.3:18619 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29616 18619 1852 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+0x71/0x310 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/0x520 arch/x86/entry/common.c:292 INFO: task syz-executor.3:18628 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29232 18628 1852 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+0x71/0x310 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/0x520 arch/x86/entry/common.c:292 INFO: task blkid:18606 blocked for more than 140 seconds. Not tainted 4.14.136+ #28 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D29248 18606 295 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:3455 [inline] path_openat+0xb6c/0x2be0 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1096 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [<000000007e69d8a8>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541 2 locks held by getty/1757: #0: (&tty->ldisc_sem){++++}, at: [<0000000066bb426f>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000c105cec3>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.0/18607: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 #1: (&lo->lo_ctl_mutex#2){+.+.}, at: [<00000000363e0c42>] loop_control_ioctl+0x183/0x310 drivers/block/loop.c:1996 2 locks held by syz-executor.5/18600: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000f53f50c1>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.}, at: [<00000000ad9c3c81>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 1 lock held by syz-executor.5/18611: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.5/18616: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.5/18621: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.3/18608: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.3/18614: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.3/18619: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.3/18628: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 2 locks held by blkid/18606: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000087d77a4e>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000abaa5d95>] lo_open+0x19/0xb0 drivers/block/loop.c:1623 1 lock held by syz-executor.2/18610: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.2/18615: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.2/18622: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.2/18624: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.1/18613: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 1 lock held by syz-executor.4/18618: #0: (loop_index_mutex){+.+.}, at: [<00000000fd7dfae0>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1982 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.136+ #28 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 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffffb0e97953