INFO: task syz-executor.0:1847 blocked for more than 140 seconds. Not tainted 4.14.107+ #33 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D24576 1847 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3492 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3550 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 loop_probe+0x73/0x180 drivers/block/loop.c:1962 kobj_lookup+0x226/0x410 drivers/base/map.c:124 get_gendisk+0x36/0x240 block/genhd.c:785 __blkdev_get+0x345/0xf90 fs/block_dev.c:1451 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x41b/0xd60 fs/open.c:764 vfs_open+0x105/0x230 fs/open.c:878 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1071 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 INFO: task syz-executor.5:1860 blocked for more than 140 seconds. Not tainted 4.14.107+ #33 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D25080 1860 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3492 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3550 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1624 __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+0x41b/0xd60 fs/open.c:764 vfs_open+0x105/0x230 fs/open.c:878 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1071 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 INFO: task syz-executor.3:1864 blocked for more than 140 seconds. Not tainted 4.14.107+ #33 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D25160 1864 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3492 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3550 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1624 __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+0x41b/0xd60 fs/open.c:764 vfs_open+0x105/0x230 fs/open.c:878 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1071 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 INFO: task syz-executor.2:7299 blocked for more than 140 seconds. Not tainted 4.14.107+ #33 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28808 7299 1853 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3492 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3550 __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:615 loop_set_status+0xbff/0x11f0 drivers/block/loop.c:1184 INFO: task syz-executor.2:7321 blocked for more than 140 seconds. Not tainted 4.14.107+ #33 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28448 7321 1853 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3492 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3550 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 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+0x41b/0xd60 fs/open.c:764 vfs_open+0x105/0x230 fs/open.c:878 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1071 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 INFO: task syz-executor.1:7306 blocked for more than 140 seconds. Not tainted 4.14.107+ #33 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D30016 7306 1846 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3492 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3550 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x17e/0x2e0 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/0x4b0 arch/x86/entry/common.c:289 INFO: task blkid:7310 blocked for more than 140 seconds. Not tainted 4.14.107+ #33 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D29000 7310 322 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3492 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3550 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1624 __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+0x41b/0xd60 fs/open.c:764 vfs_open+0x105/0x230 fs/open.c:878 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1071 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541 2 locks held by getty/1759: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:275 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.0/1847: #0: (loop_index_mutex){+.+.}, at: [] loop_probe+0x73/0x180 drivers/block/loop.c:1962 2 locks held by syz-executor.5/1860: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.3/1864: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.2/7299: #0: (loop_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x83/0x1970 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 1 lock held by syz-executor.2/7321: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 2 locks held by syz-executor.1/7306: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x71/0x2e0 drivers/block/loop.c:1982 #1: (loop_ctl_mutex#2){+.+.}, at: [] loop_control_ioctl+0x17e/0x2e0 drivers/block/loop.c:1996 2 locks held by blkid/7310: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1624 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.107+ #33 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 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff9b044912