INFO: task kworker/1:4:5329 blocked for more than 143 seconds. Not tainted 6.5.0-rc6-syzkaller-00154-gaad6ad1b780a #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:4 state:D stack:22192 pid:5329 ppid:2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0xc79/0x30a0 kernel/sched/core.c:6710 schedule+0xe7/0x1b0 kernel/sched/core.c:6786 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6845 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x967/0x1340 kernel/locking/mutex.c:747 unregister_netdev+0x12/0x30 net/core/dev.c:10923 r871xu_dev_remove+0x28e/0x480 drivers/staging/rtl8712/usb_intf.c:597 usb_unbind_interface+0x1dd/0x8d0 drivers/usb/core/driver.c:458 device_remove drivers/base/dd.c:569 [inline] device_remove+0x11f/0x170 drivers/base/dd.c:561 __device_release_driver drivers/base/dd.c:1270 [inline] device_release_driver_internal+0x44a/0x610 drivers/base/dd.c:1293 bus_remove_device+0x22c/0x420 drivers/base/bus.c:574 device_del+0x39a/0xa40 drivers/base/core.c:3814 usb_disable_device+0x36c/0x7f0 drivers/usb/core/message.c:1416 usb_disconnect+0x2e1/0x890 drivers/usb/core/hub.c:2252 hub_port_connect drivers/usb/core/hub.c:5280 [inline] hub_port_connect_change drivers/usb/core/hub.c:5580 [inline] port_event drivers/usb/core/hub.c:5740 [inline] hub_event+0x1be0/0x4f30 drivers/usb/core/hub.c:5822 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600 worker_thread+0x687/0x1110 kernel/workqueue.c:2751 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff87ea8330 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x2c/0xe20 kernel/rcu/tasks.h:522 1 lock held by rcu_tasks_trace/13: #0: ffffffff87ea8030 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x2c/0xe20 kernel/rcu/tasks.h:522 1 lock held by khungtaskd/28: #0: ffffffff87ea8f40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x340 kernel/locking/lockdep.c:6615 3 locks held by kworker/1:2/718: #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:20 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: raw_atomic64_set include/linux/atomic/atomic-arch-fallback.h:2608 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: raw_atomic_long_set include/linux/atomic/atomic-long.h:79 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:3196 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:678 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:705 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x96a/0x16f0 kernel/workqueue.c:2570 #1: ffffc900025ffd80 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x99e/0x16f0 kernel/workqueue.c:2574 #2: ffffffff88f96b68 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4635 5 locks held by kworker/0:2/2329: #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:20 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic64_set include/linux/atomic/atomic-arch-fallback.h:2608 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic_long_set include/linux/atomic/atomic-long.h:79 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:3196 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:678 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:705 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x96a/0x16f0 kernel/workqueue.c:2570 #1: ffffc90006f2fd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x99e/0x16f0 kernel/workqueue.c:2574 #2: ffff8881063c7190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #2: ffff8881063c7190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f30 drivers/usb/core/hub.c:5768 #3: ffff88810671a500 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3138 [inline] #3: ffff88810671a500 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5337 [inline] #3: ffff88810671a500 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5580 [inline] #3: ffff88810671a500 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5740 [inline] #3: ffff88810671a500 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x28b4/0x4f30 drivers/usb/core/hub.c:5822 #4: ffff888103bc4368 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5338 [inline] #4: ffff888103bc4368 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5580 [inline] #4: ffff888103bc4368 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5740 [inline] #4: ffff888103bc4368 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x28da/0x4f30 drivers/usb/core/hub.c:5822 2 locks held by dhcpcd/2412: #0: ffffffff88f96b68 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0x1d3/0x1f00 net/ipv4/devinet.c:1074 #1: ffff888117304db0 (&padapter->mutex_start){+.+.}-{3:3}, at: netdev_open+0x32/0x820 drivers/staging/rtl8712/os_intfs.c:391 2 locks held by getty/2434: #0: ffff888114b3a098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000452f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfcb/0x1480 drivers/tty/n_tty.c:2187 6 locks held by kworker/0:3/5259: #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:20 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic64_set include/linux/atomic/atomic-arch-fallback.h:2608 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic_long_set include/linux/atomic/atomic-long.h:79 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:3196 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:678 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:705 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x96a/0x16f0 kernel/workqueue.c:2570 #1: ffffc90001affd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x99e/0x16f0 kernel/workqueue.c:2574 #2: ffff888104b3f190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #2: ffff888104b3f190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f30 drivers/usb/core/hub.c:5768 #3: ffff88814303f190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #3: ffff88814303f190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7f/0x4b0 drivers/base/dd.c:1003 #4: ffff888144b8c160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #4: ffff888144b8c160 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7f/0x4b0 drivers/base/dd.c:1003 #5: ffffffff88f96b68 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x13/0x50 net/core/dev.c:10177 4 locks held by udevd/5268: #0: ffff8881202d1c30 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xda/0x1280 fs/seq_file.c:182 #1: ffff88811b3f0488 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x4b/0x460 fs/kernfs/file.c:154 #2: ffff88811f9240f0 (kn->active#33){++++}-{0:0}, at: kernfs_seq_start+0x6f/0x460 fs/kernfs/file.c:155 #3: ffff88810f254190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:963 [inline] #3: ffff88810f254190 (&dev->mutex){....}-{3:3}, at: serial_show+0x26/0xa0 drivers/usb/core/sysfs.c:143 3 locks held by kworker/0:4/5277: #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:20 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: raw_atomic64_set include/linux/atomic/atomic-arch-fallback.h:2608 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: raw_atomic_long_set include/linux/atomic/atomic-long.h:79 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:3196 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:678 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:705 [inline] #0: ffff88810a74f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x96a/0x16f0 kernel/workqueue.c:2570 #1: ffffc90001adfd80 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x99e/0x16f0 kernel/workqueue.c:2574 #2: ffffffff88f96b68 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4635 6 locks held by kworker/0:5/5307: #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:20 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic64_set include/linux/atomic/atomic-arch-fallback.h:2608 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic_long_set include/linux/atomic/atomic-long.h:79 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:3196 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:678 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:705 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x96a/0x16f0 kernel/workqueue.c:2570 #1: ffffc900024afd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x99e/0x16f0 kernel/workqueue.c:2574 #2: ffff888105f96190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #2: ffff888105f96190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f30 drivers/usb/core/hub.c:5768 #3: ffff88810f254190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #3: ffff88810f254190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7f/0x4b0 drivers/base/dd.c:1003 #4: ffff88811cf48160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #4: ffff88811cf48160 (&dev->mutex){....}-{3:3}, at: __device_attach+0x7f/0x4b0 drivers/base/dd.c:1003 #5: ffffffff88f96b68 (rtnl_mutex){+.+.}-{3:3}, at: register_netdev+0x13/0x50 net/core/dev.c:10177 6 locks held by kworker/1:4/5329: #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:20 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic64_set include/linux/atomic/atomic-arch-fallback.h:2608 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic_long_set include/linux/atomic/atomic-long.h:79 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:3196 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:678 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:705 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x96a/0x16f0 kernel/workqueue.c:2570 #1: ffffc90001b97d80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x99e/0x16f0 kernel/workqueue.c:2574 #2: ffff8881063af190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #2: ffff8881063af190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f30 drivers/usb/core/hub.c:5768 #3: ffff888109a5d190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #3: ffff888109a5d190 (&dev->mutex){....}-{3:3}, at: usb_disconnect+0x10a/0x890 drivers/usb/core/hub.c:2243 #4: ffff88810a3f9160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #4: ffff88810a3f9160 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1093 [inline] #4: ffff88810a3f9160 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa4/0x610 drivers/base/dd.c:1290 #5: ffffffff88f96b68 (rtnl_mutex){+.+.}-{3:3}, at: unregister_netdev+0x12/0x30 net/core/dev.c:10923 5 locks held by kworker/0:8/5904: #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:20 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic64_set include/linux/atomic/atomic-arch-fallback.h:2608 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: raw_atomic_long_set include/linux/atomic/atomic-long.h:79 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:3196 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:678 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:705 [inline] #0: ffff88810c654138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x96a/0x16f0 kernel/workqueue.c:2570 #1: ffffc9000d59fd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x99e/0x16f0 kernel/workqueue.c:2574 #2: ffff88810671f190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:958 [inline] #2: ffff88810671f190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f30 drivers/usb/core/hub.c:5768 #3: ffff888106742500 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3138 [inline] #3: ffff888106742500 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5337 [inline] #3: ffff888106742500 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5580 [inline] #3: ffff888106742500 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5740 [inline] #3: ffff888106742500 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x28b4/0x4f30 drivers/usb/core/hub.c:5822 #4: ffff888103b98b68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5338 [inline] #4: ffff888103b98b68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5580 [inline] #4: ffff888103b98b68 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5740 [inline] #4: ffff888103b98b68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x28da/0x4f30 drivers/usb/core/hub.c:5822 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.5.0-rc6-syzkaller-00154-gaad6ad1b780a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x277/0x380 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x27b/0x2e0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xf29/0x11b0 kernel/hung_task.c:379 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2329 Comm: kworker/0:2 Not tainted 6.5.0-rc6-syzkaller-00154-gaad6ad1b780a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Workqueue: usb_hub_wq hub_event RIP: 0010:io_serial_out+0x8f/0xb0 drivers/tty/serial/8250/8250_port.c:416 Code: 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 18 66 03 5d 40 44 89 e8 89 da ee <5b> 5d 41 5c 41 5d c3 e8 f5 43 16 ff eb a4 e8 4e 44 16 ff eb e1 66 RSP: 0018:ffffc90006f2f3e0 EFLAGS: 00000006 RAX: 0000000000000000 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: ffffffff8280bf75 RDI: ffffffff8c1ddc60 RBP: ffffffff8c1ddc20 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 205d393233325420 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8c1ddc70 R15: 0000000000000054 FS: 0000000000000000(0000) GS:ffff8881f6600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4e003d2070 CR3: 000000013f1c3000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_out drivers/tty/serial/8250/8250.h:122 [inline] serial8250_clear_IER+0xea/0x150 drivers/tty/serial/8250/8250_port.c:712 serial8250_console_write+0x1e9/0x1060 drivers/tty/serial/8250/8250_port.c:3409 console_emit_next_record kernel/printk/printk.c:2877 [inline] console_flush_all+0x4c8/0xf50 kernel/printk/printk.c:2933 console_unlock+0xc6/0x1f0 kernel/printk/printk.c:3007 vprintk_emit+0x1c5/0x640 kernel/printk/printk.c:2307 dev_vprintk_emit drivers/base/core.c:4840 [inline] dev_printk_emit+0xfb/0x140 drivers/base/core.c:4851 __dev_printk+0xf5/0x270 drivers/base/core.c:4863 _dev_info+0xe5/0x120 drivers/base/core.c:4909 hub_port_init+0xcd3/0x3920 drivers/usb/core/hub.c:4870 hub_port_connect drivers/usb/core/hub.c:5369 [inline] hub_port_connect_change drivers/usb/core/hub.c:5580 [inline] port_event drivers/usb/core/hub.c:5740 [inline] hub_event+0x2c20/0x4f30 drivers/usb/core/hub.c:5822 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2600 worker_thread+0x687/0x1110 kernel/workqueue.c:2751 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304