INFO: task syz-executor.0:1813 blocked for more than 140 seconds. Not tainted 4.14.134+ #18 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D24416 1813 1 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_clr_fd+0x835/0xad0 /drivers/block/loop.c:1068 lo_ioctl+0x460/0x1a30 /drivers/block/loop.c:1414 INFO: task syz-executor.3:19696 blocked for more than 140 seconds. Not tainted 4.14.134+ #18 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D25512 19696 1 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+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+0x44e/0xe20 /fs/open.c:770 vfs_open+0x105/0x230 /fs/open.c:884 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:1077 do_syscall_64+0x19b/0x520 /arch/x86/entry/common.c:292 INFO: task syz-executor.1:25059 blocked for more than 140 seconds. Not tainted 4.14.134+ #18 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28880 25059 15438 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.2:25060 blocked for more than 140 seconds. Not tainted 4.14.134+ #18 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28864 25060 9859 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 blkid:25061 blocked for more than 140 seconds. Not tainted 4.14.134+ #18 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D28992 25061 8654 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:770 vfs_open+0x105/0x230 /fs/open.c:884 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:1077 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: [<00000000cd4d5ef8>] debug_show_all_locks+0x7c/0x21a /kernel/locking/lockdep.c:4541 2 locks held by getty/1755: #0: (&tty->ldisc_sem){++++}, at: [<00000000bb55c516>] tty_ldisc_ref_wait+0x22/0x80 /drivers/tty/tty_ldisc.c:284 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000001deb6616>] n_tty_read+0x1f7/0x1700 /drivers/tty/n_tty.c:2156 2 locks held by syz-executor.0/1813: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000901e0462>] lo_ioctl+0x86/0x1a30 /drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.}, at: [<00000000924dc097>] blkdev_reread_part+0x1b/0x40 /block/ioctl.c:192 2 locks held by syz-executor.3/19696: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000d6293850>] __blkdev_get+0xf3/0xf90 /fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000e4514b57>] lo_open+0x19/0xb0 /drivers/block/loop.c:1623 1 lock held by syz-executor.1/25059: #0: (loop_index_mutex){+.+.}, at: [<00000000f6468c0d>] loop_control_ioctl+0x71/0x310 /drivers/block/loop.c:1982 2 locks held by syz-executor.2/25060: #0: (loop_index_mutex){+.+.}, at: [<00000000f6468c0d>] loop_control_ioctl+0x71/0x310 /drivers/block/loop.c:1982 #1: (&lo->lo_ctl_mutex#2){+.+.}, at: [<0000000053344d3a>] loop_control_ioctl+0x183/0x310 /drivers/block/loop.c:1996 2 locks held by blkid/25061: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000d6293850>] __blkdev_get+0xf3/0xf90 /fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000e4514b57>] lo_open+0x19/0xb0 /drivers/block/loop.c:1623 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.134+ #18 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 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.14.134+ #18 task: 0000000092c7b2d4 task.stack: 00000000c2c0cc17 RIP: 0010:arch_local_save_flags /./arch/x86/include/asm/paravirt.h:773 [inline] RIP: 0010:arch_local_irq_save /./arch/x86/include/asm/paravirt.h:795 [inline] RIP: 0010:lock_release+0xa6/0x740 /kernel/locking/lockdep.c:4006 RSP: 0018:ffffffffa8607bb0 EFLAGS: 00000046 RAX: 0000000000000007 RBX: 1ffffffff50c0f7a RCX: 1ffffffff50c6292 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffa863146c RBP: ffffffffa8630c40 R08: 0000000000000136 R09: 0000000000000000 R10: ffffffffa8631470 R11: 451e9e6d5d554fcd R12: ffffffffa860da08 R13: 1ffffffff50c1200 R14: 1ffffffff50c0f90 R15: ffff8881d7625018 FS: 0000000000000000(0000) GS:ffff8881d7600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000009383e0 CR3: 00000001f2426005 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: Code: 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 55 05 00 00 44 8b 8d 2c 08 00 00 45 85 c9 0f 85 3e 03 00 00 9c <58> 0f 1f 44 00 00 48 89 04 24 fa 66 0f 1f 44 00 00 65 48 8b 2c