INFO: task kworker/0:4:13499 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/0:4     D23256 13499      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:
1 lock held by khungtaskd/22:
 #0: ffffffff87109020 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5331
1 lock held by rsyslogd/1677:
 #0: ffff8881d08f2fe0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:821
2 locks held by getty/1768:
 #0: ffff8881ceeb1090 (&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/1769:
 #0: ffff8881ceeb2090 (&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/1770:
 #0: ffff8881cf3b7090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffffc900004592e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156
2 locks held by getty/1771:
 #0: ffff8881ceeb5090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffffc900004792e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156
2 locks held by getty/1772:
 #0: ffff8881ceeb0090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffffc900004692e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156
2 locks held by getty/1773:
 #0: ffff8881ceeb6090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffffc9000047d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156
2 locks held by getty/1774:
 #0: ffff8881cf0bd090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffffc9000044d2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156
6 locks held by kworker/0:5/4472:
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235
 #1: ffff8881cbecfdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239
 #2: ffff8881d4c7f200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline]
 #2: ffff8881d4c7f200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5505
 #3: ffff8881ac572200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline]
 #3: ffff8881ac572200 (&dev->mutex){....}, at: __device_attach+0x7b/0x390 drivers/base/dd.c:874
 #4: ffff8881cb116190 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline]
 #4: ffff8881cb116190 (&dev->mutex){....}, at: __device_attach+0x7b/0x390 drivers/base/dd.c:874
 #5: ffff8881acb9c680 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline]
 #5: ffff8881acb9c680 (&dev->mutex){....}, at: __device_attach+0x7b/0x390 drivers/base/dd.c:874
3 locks held by kworker/0:8/6989:
5 locks held by kworker/0:4/13499:
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235
 #1: ffff8881d39bfdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239
 #2: ffff8881d4da2200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline]
 #2: ffff8881d4da2200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5505
 #3: ffff8881c6d7f200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline]
 #3: ffff8881c6d7f200 (&dev->mutex){....}, at: usb_disconnect+0x91/0x900 drivers/usb/core/hub.c:2198
 #4: ffff8881d48c2190 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1165
3 locks held by kworker/0:11/13501:
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline]
 #0: ffff8881d889d128 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235
 #1: ffff8881d15b7dd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239
 #2: ffff8881d4d14200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline]
 #2: ffff8881d4d14200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5505
4 locks held by udevd/15535:
 #0: ffff8881ce583640 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 fs/seq_file.c:161
 #1: ffff8881c8284880 (&of->mutex){+.+.}, at: kernfs_seq_start+0x49/0x180 fs/kernfs/file.c:111
 #2: ffff8881d9251c48 (kn->count#68){++++}, at: kernfs_seq_start+0x73/0x180 fs/kernfs/file.c:112
 #3: ffff8881ac572200 (&dev->mutex){....}, at: device_lock_interruptible include/linux/device.h:776 [inline]
 #3: ffff8881ac572200 (&dev->mutex){....}, at: product_show+0x22/0xa0 drivers/usb/core/sysfs.c:140
2 locks held by syz-executor.4/21865:
 #0: ffff8881c87b5760 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:821
 #1: ffff8881d4776410 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2903 [inline]
 #1: ffff8881d4776410 (sb_writers#3){.+.+}, at: vfs_write+0x474/0x5c0 fs/read_write.c:557

=============================================

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: 4472 Comm: kworker/0:5 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:__next_timer_interrupt+0x0/0x190 kernel/time/timer.c:1507
Code: ee 5d 31 c9 41 5c 41 5d 41 5e e9 2b 84 f6 ff e8 f6 2e 38 00 eb dc e8 0f 2f 38 00 eb a6 e8 08 2f 38 00 e9 79 ff ff ff 0f 1f 00 <41> 57 41 56 41 55 41 54 55 53 48 89 fb 48 83 ec 10 e8 9a 85 0f 00
RSP: 0018:ffff8881db209e08 EFLAGS: 00000006
RAX: ffff8881c8ea8000 RBX: 0000000000000003 RCX: ffffffff81303ece
RDX: 0000000000000100 RSI: ffffffff81304abb RDI: ffff8881db226100
RBP: 000000010001634c R08: ffff8881c8ea8000 R09: ffffed103b6413b5
R10: ffffed103b6413b4 R11: 0000000000000003 R12: 000000010001634c
R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff8881db226100
FS:  0000000000000000(0000) GS:ffff8881db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc60f0d8518 CR3: 00000001afba2000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 collect_expired_timers kernel/time/timer.c:1689 [inline]
 __run_timers kernel/time/timer.c:1769 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0xdb6/0x1500 kernel/time/timer.c:1786
 __do_softirq+0x21e/0x950 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x178/0x1a0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 smp_apic_timer_interrupt+0x141/0x540 arch/x86/kernel/apic/apic.c:1146
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline]
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:1751 [inline]
RIP: 0010:vprintk_emit+0x3c8/0x3d0 kernel/printk/printk.c:1995
Code: 00 83 fb ff 75 d6 e9 e0 fc ff ff e8 12 04 16 00 e8 0d 4c 1b 00 41 56 9d e9 b6 fd ff ff e8 00 04 16 00 e8 fb 4b 1b 00 41 56 9d <e9> 2a ff ff ff 0f 1f 00 55 48 89 f5 53 48 89 fb e8 e3 03 16 00 49
RSP: 0018:ffff8881cbecf700 EFLAGS: 00000216 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: 0000000000000200 RCX: 0000000000000006
RDX: 0000000000000000 RSI: ffff8881c8ea88a0 RDI: ffff8881c8ea884c
RBP: ffff8881cbecf748 R08: ffff8881c8ea8000 R09: fffffbfff1266c8f
R10: fffffbfff1266c8e R11: ffffffff89336477 R12: 0000000000000029
R13: ffff8881da27c980 R14: 0000000000000216 R15: 0000000000000000
 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_disconnect+0x7f/0x900 drivers/usb/core/hub.c:2189
 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