INFO: task kworker/0:1:12 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/0:1 D25552 12 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: ffff8881d8841928 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d8841928 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d8841928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d8841928 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d8841928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d8841928 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d8841928 ((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: ffff8881d4cf1200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d4cf1200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5505 #3: ffff8881cda06200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #3: ffff8881cda06200 (&dev->mutex){....}, at: usb_disconnect+0x91/0x900 drivers/usb/core/hub.c:2198 #4: ffff8881ce984190 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1165 1 lock held by khungtaskd/22: #0: ffffffff87109020 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5331 2 locks held by kworker/u4:2/428: #0: ffff8881da029928 ((wq_completion)events_unbound){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881da029928 ((wq_completion)events_unbound){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881da029928 ((wq_completion)events_unbound){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881da029928 ((wq_completion)events_unbound){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881da029928 ((wq_completion)events_unbound){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881da029928 ((wq_completion)events_unbound){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881da029928 ((wq_completion)events_unbound){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881cadafdd0 ((reaper_work).work){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 1 lock held by rsyslogd/1675: 2 locks held by getty/1765: #0: ffff8881c732c090 (&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 2 locks held by getty/1766: #0: ffff8881ce441090 (&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/1767: #0: ffff8881ce93e090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900004612e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1768: #0: ffff8881ce442090 (&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: ffff8881ce938090 (&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/1770: #0: ffff8881cea27090 (&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/1771: #0: ffff8881c732a090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900004352e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 3 locks held by kworker/0:3/4534: #0: ffff8881da270d28 ((wq_completion)pm){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881da270d28 ((wq_completion)pm){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881da270d28 ((wq_completion)pm){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881da270d28 ((wq_completion)pm){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881da270d28 ((wq_completion)pm){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881da270d28 ((wq_completion)pm){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881da270d28 ((wq_completion)pm){+.+.}, at: process_one_work+0x82a/0x1620 kernel/workqueue.c:2235 #1: ffff8881d174fdd0 ((work_completion)(&hcd->wakeup_work)){+.+.}, at: process_one_work+0x85e/0x1620 kernel/workqueue.c:2239 #2: ffff8881d4d75200 (&dev->mutex){....}, at: device_lock include/linux/device.h:771 [inline] #2: ffff8881d4d75200 (&dev->mutex){....}, at: usb_remote_wakeup+0x1f/0xe0 drivers/usb/core/hub.c:3608 5 locks held by kworker/0:4/4538: ============================================= NMI backtrace for cpu 0 CPU: 0 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:native_apic_mem_write+0x8/0x10 arch/x86/include/asm/apic.h:110 Code: 00 00 5b 5d 41 5c 41 5d 41 5e c3 48 89 04 24 e8 fe d1 58 00 48 8b 04 24 eb 83 e8 13 b6 04 00 cc cc cc 89 ff 89 b7 00 c0 5f ff 0f 1f 80 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 53 89 fb 48 RSP: 0018:ffff8881db309eb8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffffffff86eda9c0 RCX: 0000000000000020 RDX: 1ffffffff0ddb53a RSI: 0000000000000af4 RDI: 0000000000000380 RBP: ffff8881db321800 R08: ffff8881da213100 R09: fffffbfff0fcc001 R10: fffffbfff0fcc000 R11: ffffffff87e60007 R12: 0000000000000af4 R13: 0000000000000000 R14: 0000000000000000 R15: ffff8881db328280 FS: 0000000000000000(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f02d95a9000 CR3: 00000001c997d000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: apic_write arch/x86/include/asm/apic.h:403 [inline] lapic_next_event+0x4d/0x80 arch/x86/kernel/apic/apic.c:468 clockevents_program_event+0x23d/0x350 kernel/time/clockevents.c:334 tick_program_event+0xad/0x140 kernel/time/tick-oneshot.c:44 hrtimer_interrupt+0x33e/0x730 kernel/time/hrtimer.c:1654 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:default_idle+0x28/0x300 arch/x86/kernel/process.c:696 Code: cc cc 41 56 41 55 65 44 8b 2d 94 c9 72 7a 41 54 55 53 0f 1f 44 00 00 e8 16 bb b5 fb e9 07 00 00 00 0f 00 2d 3a 5f 53 00 fb f4 <65> 44 8b 2d 70 c9 72 7a 0f 1f 44 00 00 5b 5d 41 5c 41 5d 41 5e c3 RSP: 0018:ffff8881da22fda8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: ffff8881da213100 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffff8881da21394c RBP: ffffed103b442620 R08: ffff8881da213100 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000001 R14: ffffffff87e60000 R15: 0000000000000000 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x3e0/0x500 kernel/sched/idle.c:269 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:361 start_secondary+0x2a4/0x390 arch/x86/kernel/smpboot.c:264 secondary_startup_64+0xb6/0xc0 arch/x86/kernel/head_64.S:242