vhci_hcd vhci_hcd.0: devid(0) speed(5) speed_str(super-speed) vhci_hcd: connection closed vhci_hcd: stop threads vhci_hcd: release socket vhci_hcd: disconnect device INFO: task kworker/1:0:18 blocked for more than 140 seconds. Not tainted 4.14.206-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:0 D27704 18 2 0x80000000 Workqueue: usb_hub_wq hub_event 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 usb_kill_urb.part.0+0x125/0x190 drivers/usb/core/urb.c:691 usb_kill_urb+0x7c/0x90 drivers/usb/core/urb.c:686 usb_start_wait_urb+0x209/0x440 drivers/usb/core/message.c:62 usb_internal_control_msg drivers/usb/core/message.c:100 [inline] usb_control_msg+0x302/0x450 drivers/usb/core/message.c:151 usb_get_descriptor+0xc0/0x160 drivers/usb/core/message.c:652 usb_get_device_descriptor+0x71/0xd0 drivers/usb/core/message.c:924 hub_port_init+0x629/0x2970 drivers/usb/core/hub.c:4647 hub_port_connect drivers/usb/core/hub.c:4905 [inline] hub_port_connect_change drivers/usb/core/hub.c:5088 [inline] port_event drivers/usb/core/hub.c:5194 [inline] hub_event+0x1923/0x3dc0 drivers/usb/core/hub.c:5274 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Showing all locks held in the system: vhci_hcd vhci_hcd.0: port 1 already used 5 locks held by kworker/1:0/18: #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 khungtaskd/1530: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1530 Comm: khungtaskd Not tainted 4.14.206-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: vhci_hcd vhci_hcd.0: pdev(0) rhport(0) sockfd(3) NMI backtrace for cpu 1 CPU: 1 PID: 14449 Comm: syz-executor.0 Not tainted 4.14.206-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880967da680 task.stack: ffff8880b36e0000 RIP: 0010:univ8250_console_write+0x0/0x70 drivers/tty/serial/8250/8250_core.c:593 RSP: 0018:ffff8880b36e77a0 EFLAGS: 00000097 RAX: ffff8880967da680 RBX: ffffffff894831e0 RCX: 000000000000054b RDX: 0000000000000040 RSI: ffffffff8be718a0 RDI: ffffffff894831e0 RBP: 0000000000000000 R08: ffffffff8b989518 R09: 00000000000c0008 R10: ffff8880967db020 R11: ffff8880967da680 R12: ffffffff8363e910 R13: ffffffff894831f0 R14: dffffc0000000000 R15: 0000000000000040 FS: 00007f69ed344700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f69ed342fd8 CR3: 00000000a5441000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: call_console_drivers kernel/printk/printk.c:1725 [inline] console_unlock+0x99d/0xf20 kernel/printk/printk.c:2400 vprintk_emit+0x224/0x620 kernel/printk/printk.c:1923 dev_vprintk_emit+0x1da/0x440 drivers/base/core.c:2989 dev_printk_emit+0xa5/0xd0 drivers/base/core.c:3000 __dev_printk+0xfe/0x250 drivers/base/core.c:3012 _dev_info+0xc5/0xf0 drivers/base/core.c:3058 store_attach+0x2fb/0x7c0 drivers/usb/usbip/vhci_sysfs.c:390 dev_attr_store+0x56/0x80 drivers/base/core.c:723 sysfs_kf_write+0x106/0x160 fs/sysfs/file.c:141 kernfs_fop_write+0x289/0x440 fs/kernfs/file.c:316 __vfs_write+0xe4/0x630 fs/read_write.c:480 vfs_write+0x17f/0x4d0 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xf2/0x210 fs/read_write.c:582 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x417751 RSP: 002b:00007f69ed3436a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 0000000000417751 RDX: 0000000000000007 RSI: 00007f69ed3436d0 RDI: 0000000000000005 RBP: 00007f69ed3436d0 R08: 0000000000000000 R09: 0000000000000007 R10: 0000000000000064 R11: 0000000000000293 R12: 00000000004d2a18 R13: 0000000000000005 R14: 0000000000000000 R15: 000000000118bf2c Code: 77 25 1d fe e9 24 ff ff ff 4c 89 f7 e8 7a 28 1d fe eb ae 4c 89 f7 e8 70 28 1d fe e9 63 ff ff ff 90 66 2e 0f 1f 84 00 00 00 00 00 <41> 54 41 89 d4 55 48 89 f5 53 48 89 fb e8 ce 55 f3 fd 48 8d 7b