INFO: task kworker/0:4:4584 blocked for more than 143 seconds. Not tainted 5.6.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:4 D23848 4584 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:2677 usb_disable_device+0x23d/0x790 drivers/usb/core/message.c:1237 usb_disconnect+0x293/0x900 drivers/usb/core/hub.c:2211 hub_port_connect drivers/usb/core/hub.c:5046 [inline] hub_port_connect_change drivers/usb/core/hub.c:5335 [inline] port_event drivers/usb/core/hub.c:5481 [inline] hub_event+0x1a1d/0x4300 drivers/usb/core/hub.c:5563 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 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: ffffffff87109060 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5331 4 locks held by kworker/0:2/95: #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881d58ffdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d4961200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d4961200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5509 #3: ffff8881d4963540 (&port_dev->status_lock){+.+.}, at: usb_lock_port drivers/usb/core/hub.c:3008 [inline] #3: ffff8881d4963540 (&port_dev->status_lock){+.+.}, at: hub_event+0x599/0x4300 drivers/usb/core/hub.c:5562 1 lock held by rsyslogd/1680: 2 locks held by getty/1771: #0: ffff8881ce4c7090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000087f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1772: #0: ffff8881ce6b3090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900008992e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1773: #0: ffff8881ce5a1090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900008a12e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1774: #0: ffff8881ce6cd090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900008912e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1775: #0: ffff8881cf565090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900008872e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1776: #0: ffff8881ce437090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000086f2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 8 locks held by kworker/1:3/4518: 5 locks held by kworker/0:4/4584: #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d8d3cd28 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881cb80fdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d487c200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d487c200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5509 #3: ffff8881d8864200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #3: ffff8881d8864200 (&dev->mutex){....}, at: usb_disconnect+0x91/0x900 drivers/usb/core/hub.c:2202 #4: ffff8881adec5190 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1165 3 locks held by kworker/0:10/4612: 2 locks held by getty/6249: #0: ffff8881c7c52090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900103d82e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 5.6.0-rc5-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4518 Comm: kworker/1:3 Not tainted 5.6.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: usb_hub_wq hub_event RIP: 0010:__lock_is_held kernel/locking/lockdep.c:4303 [inline] RIP: 0010:lock_is_held_type+0x12c/0x240 kernel/locking/lockdep.c:4521 Code: 25 e9 d5 00 00 00 41 0f b6 45 00 83 c3 01 84 c0 74 08 3c 03 0f 8e 04 01 00 00 3b 9d 48 08 00 00 0f 8d b5 00 00 00 48 8b 34 24 <48> 63 c3 48 8d 04 80 4c 8d 3c c6 4c 89 f6 4c 89 ff e8 9e ec ff ff RSP: 0018:ffff8881db309d70 EFLAGS: 00000097 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8881ce0ba0d0 RDI: ffff8881ce0ba142 RBP: ffff8881ce0b9880 R08: ffff8881ce0b9880 R09: ffffed103b666a8c R10: ffffed103b666a8b R11: ffff8881db33545b R12: ffff8881ce0ba0c8 R13: ffffed1039c17419 R14: ffffffff87108fe0 R15: ffff8881ce0ba120 FS: 0000000000000000(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdb1227c000 CR3: 00000001b3c27000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held include/linux/lockdep.h:361 [inline] rcu_read_lock_sched_held+0x9c/0xd0 kernel/rcu/update.c:121 trace_hrtimer_cancel include/trace/events/timer.h:290 [inline] debug_deactivate kernel/time/hrtimer.c:483 [inline] __run_hrtimer kernel/time/hrtimer.c:1487 [inline] __hrtimer_run_queues+0xb16/0xd20 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x2e8/0x730 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1119 [inline] smp_apic_timer_interrupt+0xfe/0x540 arch/x86/kernel/apic/apic.c:1144 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 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 e2 01 16 00 e8 dd 4a 1b 00 41 56 9d e9 b6 fd ff ff e8 d0 01 16 00 e8 cb 4a 1b 00 41 56 9d 2a ff ff ff 0f 1f 00 55 48 89 f5 53 48 89 fb e8 b3 01 16 00 49 RSP: 0018:ffff8881ccfd7700 EFLAGS: 00000216 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: 0000000000000200 RCX: 0000000000000006 RDX: 0000000000000000 RSI: ffff8881ce0ba120 RDI: ffff8881ce0ba0cc RBP: ffff8881ccfd7748 R08: ffff8881ce0b9880 R09: fffffbfff1266e8f R10: fffffbfff1266e8e R11: ffffffff89337477 R12: 000000000000004d R13: ffff8881d8c80000 R14: 0000000000000216 R15: 0000000000000000 dev_vprintk_emit+0x4fc/0x541 drivers/base/core.c:3616 dev_printk_emit+0xba/0xf1 drivers/base/core.c:3627 __dev_printk+0x1db/0x203 drivers/base/core.c:3639 _dev_info+0xd7/0x109 drivers/base/core.c:3685 announce_device drivers/usb/core/hub.c:2269 [inline] usb_new_device.cold+0x185/0xcd0 drivers/usb/core/hub.c:2528 hub_port_connect drivers/usb/core/hub.c:5195 [inline] hub_port_connect_change drivers/usb/core/hub.c:5335 [inline] port_event drivers/usb/core/hub.c:5481 [inline] hub_event+0x21cb/0x4300 drivers/usb/core/hub.c:5563 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