INFO: task systemd-udevd:4627 blocked for more than 140 seconds. Not tainted 4.14.228-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-udevd D25768 4627 1 0x00000104 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1634 __blkdev_get+0xa8c/0x1090 fs/block_dev.c:1537 blkdev_get+0x88/0x890 fs/block_dev.c:1611 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x628/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7fe635869840 RSP: 002b:00007ffe6aa35288 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007ffe6aa35360 RCX: 00007fe635869840 RDX: 00005625a55b0fe3 RSI: 00000000000a0800 RDI: 00005625a691a900 RBP: 0000000000000000 R08: 00005625a55b0670 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe6aa35430 R13: 00005625a690d010 R14: 00005625a691c500 R15: 00007ffe6aa35300 INFO: task syz-executor039:8004 blocked for more than 140 seconds. Not tainted 4.14.228-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor039 D28912 8004 8003 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1993 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x440009 RSP: 002b:00007ffd371b6468 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 0000000000440009 RDX: 0000000000000000 RSI: 0000000000004c82 RDI: 0000000000000003 RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d R10: 000000000000000d R11: 0000000000000246 R12: 0000000000403750 R13: 00007ffd371b6490 R14: 00007ffd371b647c R15: 00007ffd371b6480 INFO: task syz-executor039:8005 blocked for more than 140 seconds. Not tainted 4.14.228-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor039 D28664 8005 8001 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 loop_control_ioctl+0x181/0x3f0 drivers/block/loop.c:2007 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x440009 RSP: 002b:00007ffd371b6468 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 0000000000440009 RDX: 0000000000000002 RSI: 0000000000004c81 RDI: 0000000000000004 RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d R10: 000000000000000d R11: 0000000000000246 R12: 0000000000403750 R13: 00007ffd371b6490 R14: 00007ffd371b647c R15: 00007ffd371b6480 INFO: task syz-executor039:8015 blocked for more than 140 seconds. Not tainted 4.14.228-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor039 D28912 8015 8002 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 lo_release+0x1b/0x190 drivers/block/loop.c:1677 __blkdev_put+0x5aa/0x800 fs/block_dev.c:1803 blkdev_close+0x86/0xb0 fs/block_dev.c:1875 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x4024a3 RSP: 002b:00007ffd371b6208 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 00007ffd371b6230 RCX: 00000000004024a3 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004 RBP: 0000000000000004 R08: 0000000000000001 R09: 00007ffd371b60a0 R10: 00007ffd371b5f57 R11: 0000000000000246 R12: 0000000000000003 R13: 00000000006ff2c0 R14: 00007ffd371b62b0 R15: 0000000000000008 INFO: task syz-executor039:8019 blocked for more than 140 seconds. Not tainted 4.14.228-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor039 D28912 8019 8000 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 loop_reread_partitions drivers/block/loop.c:624 [inline] loop_clr_fd+0x9ca/0xc20 drivers/block/loop.c:1078 lo_ioctl+0x895/0x1cd0 drivers/block/loop.c:1424 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x540/0x1830 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x43feb7 RSP: 002b:00007ffd371b6208 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffd371b6230 RCX: 000000000043feb7 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004 RBP: 0000000000000004 R08: 0000000000000001 R09: 00007ffd371b60a0 R10: 00007ffd371b5f57 R11: 0000000000000246 R12: 0000000000000003 R13: 00000000006ff2c0 R14: 00007ffd371b62b0 R15: 0000000000000008 INFO: task syz-executor039:8030 blocked for more than 140 seconds. Not tainted 4.14.228-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor039 D28864 8030 7999 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 lo_release+0x1b/0x190 drivers/block/loop.c:1677 __blkdev_put+0x5aa/0x800 fs/block_dev.c:1803 blkdev_close+0x86/0xb0 fs/block_dev.c:1875 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x4024a3 RSP: 002b:00007ffd371b6208 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 00007ffd371b6230 RCX: 00000000004024a3 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004 RBP: 0000000000000004 R08: 0000000000000001 R09: 00007ffd371b60a0 R10: 00007ffd371b5f57 R11: 0000000000000246 R12: 0000000000000003 R13: 00000000006ff2c0 R14: 00007ffd371b62b0 R15: 0000000000000008 INFO: task systemd-udevd:8036 blocked for more than 140 seconds. Not tainted 4.14.228-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-udevd D28880 8036 4627 0x00000100 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1634 __blkdev_get+0xa8c/0x1090 fs/block_dev.c:1537 blkdev_get+0x88/0x890 fs/block_dev.c:1611 blkdev_open+0x1cc/0x250 fs/block_dev.c:1772 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0x628/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7fe635869840 RSP: 002b:00007ffe6aa2fd98 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00005625a690ddc0 RCX: 00007fe635869840 RDX: 00005625a55b0fe3 RSI: 0000000000080000 RDI: 00005625a6911820 RBP: 0000000000000001 R08: 00005625a55b0670 R09: 0000000000000110 R10: 00000000000002fe R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00005625a6911530 R15: 00000000ffffffff INFO: task syz-executor039:8042 blocked for more than 140 seconds. Not tainted 4.14.228-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor039 D28912 8042 7998 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893 loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1993 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x440009 RSP: 002b:00007ffd371b6468 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 0000000000440009 RDX: 0000000000000000 RSI: 0000000000004c82 RDI: 0000000000000003 RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d R10: 000000000000000d R11: 0000000000000246 R12: 00000000000b8a53 R13: 00007ffd371b6490 R14: 00007ffd371b647c R15: 00007ffd371b6480 Showing all locks held in the system: 1 lock held by khungtaskd/1532: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by systemd-udevd/4627: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1634 1 lock held by in:imklog/7660: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x1fb/0x2b0 fs/file.c:769 1 lock held by syz-executor039/8004: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1993 2 locks held by syz-executor039/8005: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1993 #1: (&lo->lo_ctl_mutex){+.+.}, at: [] loop_control_ioctl+0x181/0x3f0 drivers/block/loop.c:2007 2 locks held by syz-executor039/8015: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_put+0xd8/0x800 fs/block_dev.c:1790 #1: (loop_index_mutex){+.+.}, at: [] lo_release+0x1b/0x190 drivers/block/loop.c:1677 2 locks held by syz-executor039/8019: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x87/0x1cd0 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 2 locks held by syz-executor039/8030: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_put+0xd8/0x800 fs/block_dev.c:1790 #1: (loop_index_mutex){+.+.}, at: [] lo_release+0x1b/0x190 drivers/block/loop.c:1677 2 locks held by systemd-udevd/8036: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1634 1 lock held by syz-executor039/8042: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1993 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1532 Comm: khungtaskd Not tainted 4.14.228-syzkaller #0 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+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5b9/0xb40 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff87223bce