INFO: task kworker/1:2:2649 blocked for more than 140 seconds. Not tainted 4.14.225-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:2 D27432 2649 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+0x18fd/0x3d70 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: 1 lock held by khungtaskd/1528: #0: (tasklist_lock){.+.?}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 5 locks held by kworker/1:2/2649: #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+0x108/0x3d70 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+0x18e8/0x3d70 drivers/usb/core/hub.c:5274 #4: (hcd->address0_mutex){+.+.}, at: [] hub_port_init+0x15b/0x2970 drivers/usb/core/hub.c:4429 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1528 Comm: khungtaskd Not tainted 4.14.225-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 CPU: 1 PID: 22587 Comm: syz-executor.4 Not tainted 4.14.225-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880439e8440 task.stack: ffff88804b470000 RIP: 0010:__lock_acquire+0x60/0x3f20 kernel/locking/lockdep.c:3348 RSP: 0018:ffff88804b4775b0 EFLAGS: 00000086 RAX: ffffed100968eeca RBX: 0000000000000000 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8880a1d6fc08 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: ffff88804b477a77 R11: ffff8880439e8440 R12: ffff8880a1d6fc08 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001 FS: 00007fced6cc4700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb1fb990740 CR3: 0000000098e52000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 unix_dgram_recvmsg+0x1e3/0xd10 net/unix/af_unix.c:2135 ___sys_recvmsg+0x20b/0x4d0 net/socket.c:2221 __sys_recvmmsg+0x1f3/0x5d0 net/socket.c:2329 SYSC_recvmmsg net/socket.c:2405 [inline] SyS_recvmmsg+0x125/0x140 net/socket.c:2394 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x465f69 RSP: 002b:00007fced6cc4188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465f69 RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000005 RBP: 00000000004bfa8f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 000000000056c008 R13: 00007ffd4bab4e0f R14: 00007fced6cc4300 R15: 0000000000022000 Code: 41 48 c7 84 24 a8 00 00 00 00 68 b5 88 48 c1 e8 03 48 89 44 24 08 48 01 d0 48 c7 84 24 b0 00 00 00 d0 63 41 81 c7 00 f1 f1 f1 f1 40 04 00 f2 f2 f2 c7 40 08 00 00 00 f2 c7 40 0c f2 f2 f2 f2