INFO: task syz-executor.0:31347 blocked for more than 140 seconds. Not tainted 4.14.212-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29776 31347 15455 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 device_lock include/linux/device.h:1081 [inline] usbdev_open+0x142/0x780 drivers/usb/core/devio.c:1023 chrdev_open+0x23c/0x6d0 fs/char_dev.c:423 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: 0033:0x417c41 RSP: 002b:00007f6313fc7810 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000417c41 RDX: 0000000000000000 RSI: 00000000000e8381 RDI: 00007f6313fc7840 RBP: 000000000119bfc0 R08: 000000000000000f R09: 0000000000000000 R10: 00007f6313fc89d0 R11: 0000000000000293 R12: 000000000119bf8c R13: 00007fff59e5179f R14: 00007f6313fc89c0 R15: 000000000119bf8c Showing all locks held in the system: 1 lock held by khungtaskd/1531: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 5 locks held by kworker/1:2/3273: #0: ("usb_hub_wq"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2087 #1: ((&hub->events)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2091 #2: (&dev->mutex){....}, at: [] device_lock include/linux/device.h:1081 [inline] #2: (&dev->mutex){....}, at: [] hub_event+0x108/0x3dc0 drivers/usb/core/hub.c:5220 #3: (&port_dev->status_lock){+.+.}, at: [] usb_lock_port drivers/usb/core/hub.c:2934 [inline] #3: (&port_dev->status_lock){+.+.}, at: [] hub_port_connect drivers/usb/core/hub.c:4904 [inline] #3: (&port_dev->status_lock){+.+.}, at: [] hub_port_connect_change drivers/usb/core/hub.c:5088 [inline] #3: (&port_dev->status_lock){+.+.}, at: [] port_event drivers/usb/core/hub.c:5194 [inline] #3: (&port_dev->status_lock){+.+.}, at: [] hub_event+0x190e/0x3dc0 drivers/usb/core/hub.c:5274 #4: (hcd->address0_mutex){+.+.}, at: [] hub_port_init+0x15b/0x2970 drivers/usb/core/hub.c:4429 1 lock held by systemd-journal/4605: #0: (&rq->lock){-.-.}, at: [] rq_lock kernel/sched/sched.h:1747 [inline] #0: (&rq->lock){-.-.}, at: [] __schedule+0x1df/0x1de0 kernel/sched/core.c:3321 1 lock held by syz-executor.0/31347: #0: (&dev->mutex){....}, at: [] device_lock include/linux/device.h:1081 [inline] #0: (&dev->mutex){....}, at: [] usbdev_open+0x142/0x780 drivers/usb/core/devio.c:1023 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1531 Comm: khungtaskd Not tainted 4.14.212-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+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f 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 CPU: 1 PID: 4605 Comm: systemd-journal Not tainted 4.14.212-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880a2100380 task.stack: ffff8880a2108000 RIP: 0033:0x7ff748f31f80 RSP: 002b:00007fff3c228e58 EFLAGS: 00000206 RAX: 000000002a9ff4ed RBX: 00005611ce3f8310 RCX: 000000000001ec2d RDX: 0000000000000000 RSI: 000000002a9e08c0 RDI: 431bde82d7b634db RBP: 00007fff3c229060 R08: 00007fff3c2ac000 R09: 000000c0e4153133 R10: 0003c147e8e2ac63 R11: 0000000000000001 R12: 00007fff3c228e70 R13: 0000000000000001 R14: 0000000000000001 R15: 0005b7376035f5e1 FS: 00007ff7492658c0(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff746793000 CR3: 00000000a212f000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400