INFO: task kworker/1:3:4530 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:3 D23600 4530 2 0x80004000 Workqueue: usb_hub_wq hub_event Call Trace: schedule+0xcd/0x2b0 kernel/sched/core.c:4154 schedule_timeout+0x682/0xb20 kernel/time/timer.c:1871 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x26f/0x3c0 kernel/sched/completion.c:136 kthread_stop+0x17a/0x780 kernel/kthread.c:559 hwrng_unregister+0x24f/0x330 drivers/char/hw_random/core.c:556 chaoskey_disconnect+0x216/0x290 drivers/usb/misc/chaoskey.c:232 usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:436 __device_release_driver drivers/base/dd.c:1137 [inline] device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1168 bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533 device_del+0x481/0xd30 drivers/base/core.c:2664 usb_disable_device+0x23d/0x790 drivers/usb/core/message.c:1237 usb_disconnect+0x293/0x900 drivers/usb/core/hub.c:2207 hub_port_connect drivers/usb/core/hub.c:5042 [inline] hub_port_connect_change drivers/usb/core/hub.c:5331 [inline] port_event drivers/usb/core/hub.c:5477 [inline] hub_event+0x1a1d/0x4300 drivers/usb/core/hub.c:5559 process_one_work+0x94b/0x1620 kernel/workqueue.c:2264 process_scheduled_works kernel/workqueue.c:2326 [inline] worker_thread+0x7ab/0xe20 kernel/workqueue.c:2412 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Showing all locks held in the system: 5 locks held by kworker/0:1/12: #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881da227dd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d4d84200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d4d84200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5505 #3: ffff8881d4d86540 (&port_dev->status_lock){+.+.}, at: usb_lock_port drivers/usb/core/hub.c:3004 [inline] #3: ffff8881d4d86540 (&port_dev->status_lock){+.+.}, at: hub_port_connect drivers/usb/core/hub.c:5122 [inline] #3: ffff8881d4d86540 (&port_dev->status_lock){+.+.}, at: hub_port_connect_change drivers/usb/core/hub.c:5331 [inline] #3: ffff8881d4d86540 (&port_dev->status_lock){+.+.}, at: port_event drivers/usb/core/hub.c:5477 [inline] #3: ffff8881d4d86540 (&port_dev->status_lock){+.+.}, at: hub_event+0x1fae/0x4300 drivers/usb/core/hub.c:5559 #4: ffff8881d5346760 (hcd->address0_mutex){+.+.}, at: hub_port_init+0x1b6/0x2e60 drivers/usb/core/hub.c:4546 6 locks held by kworker/1:0/17: #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881da267dd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d4cc7200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d4cc7200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5505 #3: ffff8881cdabf200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #3: ffff8881cdabf200 (&dev->mutex){....}, at: usb_disconnect+0x91/0x900 drivers/usb/core/hub.c:2198 #4: ffff8881d46bb190 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1165 #5: ffffffff877c7480 (input_mutex){+.+.}, at: __input_unregister_device+0x118/0x430 drivers/input/input.c:2087 1 lock held by khungtaskd/22: #0: ffffffff87109020 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5331 5 locks held by kworker/1:1/78: #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881d8ecfdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d4cc0200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d4cc0200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5505 #3: ffff8881adfc5200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #3: ffff8881adfc5200 (&dev->mutex){....}, at: __device_attach+0x7b/0x390 drivers/base/dd.c:874 #4: ffff8881d935c190 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #4: ffff8881d935c190 (&dev->mutex){....}, at: __device_attach+0x7b/0x390 drivers/base/dd.c:874 6 locks held by kworker/0:2/102: #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881d4f7fdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d4cfe200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d4cfe200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5505 #3: ffff8881adede200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #3: ffff8881adede200 (&dev->mutex){....}, at: __device_attach+0x7b/0x390 drivers/base/dd.c:874 #4: ffff8881adedc190 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #4: ffff8881adedc190 (&dev->mutex){....}, at: __device_attach+0x7b/0x390 drivers/base/dd.c:874 #5: ffff8881c83032c8 (&priv->usb_buf_mutex){+.+.}, at: rtl8xxxu_read32+0x54/0x130 drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c:695 1 lock held by rsyslogd/1677: #0: ffff8881cfdd6d60 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:821 2 locks held by getty/1769: #0: ffff8881ceed2090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900004512e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1770: #0: ffff8881ceed3090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900004552e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1771: #0: ffff8881cedcd090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900004712e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1772: #0: ffff8881cedd6090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000046d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1773: #0: ffff8881cedcf090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900004752e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1774: #0: ffff8881cf6fa090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000043d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 5 locks held by kworker/1:3/4530: #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d897c128 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881ac777dd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d4c89200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d4c89200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5505 #3: ffff8881d2cea200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #3: ffff8881d2cea200 (&dev->mutex){....}, at: usb_disconnect+0x91/0x900 drivers/usb/core/hub.c:2198 #4: ffff8881d889d190 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1165 2 locks held by getty/9552: #0: ffff8881ad434090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000f8fa2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 22 Comm: khungtaskd Not tainted 5.6.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xef/0x16e lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1db/0x207 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa99/0xfd0 kernel/hung_task.c:289 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.6.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event RIP: 0010:io_serial_in+0x60/0x80 drivers/tty/serial/8250/8250_port.c:447 Code: 0f b6 8d e9 00 00 00 48 8d 7d 38 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 13 03 5d 38 89 da ec <5b> 0f b6 c0 5d c3 e8 e5 d2 49 ff eb c9 e8 0e d3 49 ff eb e6 66 90 RSP: 0018:ffff8881da226ff8 EFLAGS: 00000002 RAX: dffffc0000000060 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff821e324c RDI: ffffffff89ff9b38 RBP: ffffffff89ff9b00 R08: ffff8881da211880 R09: ffffed103b444e05 R10: ffffed103b444e04 R11: 0000000000000003 R12: 0000000000000020 R13: fffffbfff13ff3af R14: fffffbfff13ff369 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2aad096c10 CR3: 00000001afb10000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_in drivers/tty/serial/8250/8250.h:113 [inline] wait_for_xmitr+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1968 serial8250_console_putchar+0x1b/0x50 drivers/tty/serial/8250/8250_port.c:3100 uart_console_write+0x59/0x100 drivers/tty/serial/serial_core.c:1928 serial8250_console_write+0x2f8/0x880 drivers/tty/serial/8250/8250_port.c:3164 call_console_drivers kernel/printk/printk.c:1791 [inline] console_unlock+0x8be/0xca0 kernel/printk/printk.c:2473 vprintk_emit+0x171/0x3d0 kernel/printk/printk.c:1996 dev_vprintk_emit+0x4fc/0x541 drivers/base/core.c:3603 dev_printk_emit+0xba/0xf1 drivers/base/core.c:3614 __dev_printk+0x1db/0x203 drivers/base/core.c:3626 _dev_info+0xd7/0x109 drivers/base/core.c:3672 usb_get_langid drivers/usb/core/message.c:785 [inline] usb_string.cold+0xeb/0x148 drivers/usb/core/message.c:832 usb_cache_string+0x7e/0x110 drivers/usb/core/message.c:878 usb_set_configuration+0x13ee/0x17d0 drivers/usb/core/message.c:1995 usb_generic_driver_probe+0x9d/0xe0 drivers/usb/core/generic.c:241 usb_probe_device+0xd9/0x230 drivers/usb/core/driver.c:272 really_probe+0x290/0xac0 drivers/base/dd.c:551 driver_probe_device+0x223/0x350 drivers/base/dd.c:724 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:831 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:431 __device_attach+0x217/0x390 drivers/base/dd.c:897 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0x1459/0x1bf0 drivers/base/core.c:2487 usb_new_device.cold+0x540/0xcd0 drivers/usb/core/hub.c:2544 hub_port_connect drivers/usb/core/hub.c:5191 [inline] hub_port_connect_change drivers/usb/core/hub.c:5331 [inline] port_event drivers/usb/core/hub.c:5477 [inline] hub_event+0x21cb/0x4300 drivers/usb/core/hub.c:5559 process_one_work+0x94b/0x1620 kernel/workqueue.c:2264 worker_thread+0x96/0xe20 kernel/workqueue.c:2410 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352