INFO: task syz-executor.1:31231 blocked for more than 140 seconds. Not tainted 4.14.155-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D25312 31231 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3499 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557 __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: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+0x44e/0xe20 fs/open.c:789 vfs_open+0x105/0x230 fs/open.c:903 do_last fs/namei.c:3539 [inline] path_openat+0xb6c/0x2be0 fs/namei.c:3681 do_filp_open+0x1a1/0x280 fs/namei.c:3715 do_sys_open+0x2ca/0x590 fs/open.c:1096 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4143b0 RSP: 002b:00007fffa64d2c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000090340 RCX: 00000000004143b0 RDX: 00007fffa64d2cea RSI: 0000000000000002 RDI: 00007fffa64d2ce0 RBP: 000000000000013e R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffa64d2c90 R14: 000000000009031e R15: 00007fffa64d2ca0 INFO: task syz-executor.2:32544 blocked for more than 140 seconds. Not tainted 4.14.155-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D25312 32544 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3499 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557 __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: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+0x44e/0xe20 fs/open.c:789 vfs_open+0x105/0x230 fs/open.c:903 do_last fs/namei.c:3539 [inline] path_openat+0xb6c/0x2be0 fs/namei.c:3681 do_filp_open+0x1a1/0x280 fs/namei.c:3715 do_sys_open+0x2ca/0x590 fs/open.c:1096 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4143b0 RSP: 002b:00007ffc60841358 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00000000000900f6 RCX: 00000000004143b0 RDX: 00007ffc608413ea RSI: 0000000000000002 RDI: 00007ffc608413e0 RBP: 00000000000000f9 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc60841390 R14: 000000000009003b R15: 00007ffc608413a0 INFO: task syz-executor.5:1147 blocked for more than 140 seconds. Not tainted 4.14.155-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D25312 1147 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3499 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557 __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: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+0x44e/0xe20 fs/open.c:789 vfs_open+0x105/0x230 fs/open.c:903 do_last fs/namei.c:3539 [inline] path_openat+0xb6c/0x2be0 fs/namei.c:3681 do_filp_open+0x1a1/0x280 fs/namei.c:3715 do_sys_open+0x2ca/0x590 fs/open.c:1096 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4143b0 RSP: 002b:00007fff8c420e18 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000090162 RCX: 00000000004143b0 RDX: 00007fff8c420eaa RSI: 0000000000000002 RDI: 00007fff8c420ea0 RBP: 00000000000000aa R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff8c420e50 R14: 000000000008fe17 R15: 00007fff8c420e60 INFO: task syz-executor.4:2987 blocked for more than 140 seconds. Not tainted 4.14.155-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D25312 2987 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3499 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557 __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: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+0x44e/0xe20 fs/open.c:789 vfs_open+0x105/0x230 fs/open.c:903 do_last fs/namei.c:3539 [inline] path_openat+0xb6c/0x2be0 fs/namei.c:3681 do_filp_open+0x1a1/0x280 fs/namei.c:3715 do_sys_open+0x2ca/0x590 fs/open.c:1096 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4143b0 RSP: 002b:00007ffe83cf4878 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000090099 RCX: 00000000004143b0 RDX: 00007ffe83cf490a RSI: 0000000000000002 RDI: 00007ffe83cf4900 RBP: 000000000000004a R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe83cf48b0 R14: 0000000000090040 R15: 00007ffe83cf48c0 INFO: task syz-executor.0:4070 blocked for more than 140 seconds. Not tainted 4.14.155-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D26208 4070 28461 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3499 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557 __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 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x8d0/0x1870 block/ioctl.c:594 block_ioctl+0xd9/0x120 fs/block_dev.c:1881 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 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a4a7 RSP: 002b:00007fab176aa9f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fab176ab6d4 RCX: 000000000045a4a7 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000006 RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000000c R10: 0000000000000064 R11: 0000000000000246 R12: 0000000000000005 R13: 0000000000000000 R14: 0000000000000006 R15: 00000000ffffffff INFO: task syz-executor.3:4071 blocked for more than 140 seconds. Not tainted 4.14.155-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28816 4071 3311 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3499 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557 __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:1997 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 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a639 RSP: 002b:00007f2154adcc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a639 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2154add6d4 R13: 00000000004c409c R14: 00000000004d8698 R15: 00000000ffffffff INFO: task syz-executor.3:4086 blocked for more than 140 seconds. Not tainted 4.14.155-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D29792 4086 3311 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3499 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557 __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:1983 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 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a639 RSP: 002b:00007f2154abbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a639 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000005 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2154abc6d4 R13: 00000000004c409c R14: 00000000004d8698 R15: 00000000ffffffff INFO: task blkid:4073 blocked for more than 140 seconds. Not tainted 4.14.155-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D28864 4073 2058 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3499 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3557 __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: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+0x44e/0xe20 fs/open.c:789 vfs_open+0x105/0x230 fs/open.c:903 do_last fs/namei.c:3539 [inline] path_openat+0xb6c/0x2be0 fs/namei.c:3681 do_filp_open+0x1a1/0x280 fs/namei.c:3715 do_sys_open+0x2ca/0x590 fs/open.c:1096 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7fdccbb4a120 RSP: 002b:00007fff60b5bb08 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdccbb4a120 RDX: 00007fff60b5cf41 RSI: 0000000000000000 RDI: 00007fff60b5cf41 RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000001c44030 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [<00000000c0a2c5a7>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544 2 locks held by getty/1763: #0: (&tty->ldisc_sem){++++}, at: [<000000002f0e04ad>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000e56bacbc>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.1/31231: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000e43e13eb>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000ca0541e3>] lo_open+0x19/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.2/32544: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000e43e13eb>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000ca0541e3>] lo_open+0x19/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.5/1147: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000e43e13eb>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000ca0541e3>] lo_open+0x19/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.4/2987: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000e43e13eb>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000ca0541e3>] lo_open+0x19/0xb0 drivers/block/loop.c:1624 2 locks held by syz-executor.0/4070: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000b0f57694>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.}, at: [<00000000c4ce31e5>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 2 locks held by syz-executor.3/4071: #0: (loop_index_mutex){+.+.}, at: [<0000000039bb203d>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1983 #1: (&lo->lo_ctl_mutex#2){+.+.}, at: [<000000002395ee59>] loop_control_ioctl+0x183/0x310 drivers/block/loop.c:1997 1 lock held by syz-executor.3/4086: #0: (loop_index_mutex){+.+.}, at: [<0000000039bb203d>] loop_control_ioctl+0x71/0x310 drivers/block/loop.c:1983 2 locks held by blkid/4073: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000e43e13eb>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000ca0541e3>] lo_open+0x19/0xb0 drivers/block/loop.c:1624 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.155-syzkaller #0 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xe5/0x154 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x119/0x147 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+0x629/0xbe0 kernel/hung_task.c:274 kthread+0x31f/0x430 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff970a6c73