INFO: task kworker/0:6:3890 blocked for more than 143 seconds. Not tainted 5.5.0-rc2-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:6 D23448 3890 2 0x80004000 Workqueue: usb_hub_wq hub_event Call Trace: schedule+0xcd/0x2b0 kernel/sched/core.c:4155 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+0x160/0x6e0 kernel/kthread.c:559 dvb_ca_en50221_release+0x91/0x1d0 drivers/media/dvb-core/dvb_ca_en50221.c:1934 az6027_ci_uninit drivers/media/usb/dvb-usb/az6027.c:728 [inline] az6027_usb_disconnect+0xa0/0xe0 drivers/media/usb/dvb-usb/az6027.c:934 usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423 __device_release_driver drivers/base/dd.c:1134 [inline] device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165 bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:532 device_del+0x481/0xd30 drivers/base/core.c:2664 usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237 usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2200 hub_port_connect drivers/usb/core/hub.c:5035 [inline] hub_port_connect_change drivers/usb/core/hub.c:5324 [inline] port_event drivers/usb/core/hub.c:5470 [inline] hub_event+0x1753/0x3860 drivers/usb/core/hub.c:5552 process_one_work+0x92b/0x1530 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: 5 locks held by kworker/0:1/12: #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x827/0x1530 kernel/workqueue.c:2235 #1: ffff8881da227dd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85b/0x1530 kernel/workqueue.c:2239 #2: ffff8881d52e9200 (&dev->mutex){....}, at: device_lock include/linux/device.h:1493 [inline] #2: ffff8881d52e9200 (&dev->mutex){....}, at: hub_event+0x1b2/0x3860 drivers/usb/core/hub.c:5498 #3: ffff8881d52eb540 (&port_dev->status_lock){+.+.}, at: usb_lock_port drivers/usb/core/hub.c:2997 [inline] #3: ffff8881d52eb540 (&port_dev->status_lock){+.+.}, at: hub_port_connect drivers/usb/core/hub.c:5115 [inline] #3: ffff8881d52eb540 (&port_dev->status_lock){+.+.}, at: hub_port_connect_change drivers/usb/core/hub.c:5324 [inline] #3: ffff8881d52eb540 (&port_dev->status_lock){+.+.}, at: port_event drivers/usb/core/hub.c:5470 [inline] #3: ffff8881d52eb540 (&port_dev->status_lock){+.+.}, at: hub_event+0x1c67/0x3860 drivers/usb/core/hub.c:5552 #4: ffff8881d528e060 (hcd->address0_mutex){+.+.}, at: hub_port_init+0x1b6/0x2d30 drivers/usb/core/hub.c:4539 1 lock held by khungtaskd/23: #0: ffffffff86eff520 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5332 1 lock held by rsyslogd/1597: #0: ffff8881d30e4360 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:801 2 locks held by getty/1689: #0: ffff8881d239d090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900004412e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1690: #0: ffff8881d1b28090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900004492e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1691: #0: ffff8881d15fa090 (&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/1692: #0: ffff8881d1bb0090 (&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/1693: #0: ffff8881d1ae7090 (&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/1694: #0: ffff8881d54ba090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900001c12e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 5 locks held by kworker/0:2/3222: 3 locks held by kworker/0:3/3307: 3 locks held by kworker/0:4/3313: 5 locks held by kworker/0:6/3890: #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d8d77528 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x827/0x1530 kernel/workqueue.c:2235 #1: ffff8881c7277dd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85b/0x1530 kernel/workqueue.c:2239 #2: ffff8881d51ed200 (&dev->mutex){....}, at: device_lock include/linux/device.h:1493 [inline] #2: ffff8881d51ed200 (&dev->mutex){....}, at: hub_event+0x1b2/0x3860 drivers/usb/core/hub.c:5498 #3: ffff8881ce827200 (&dev->mutex){....}, at: device_lock include/linux/device.h:1493 [inline] #3: ffff8881ce827200 (&dev->mutex){....}, at: usb_disconnect+0x91/0x8d0 drivers/usb/core/hub.c:2191 #4: ffff8881ce825190 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1162 5 locks held by kworker/0:0/23025: 5 locks held by kdvb-ca-0:0/30252: 2 locks held by getty/30439: #0: ffff8881adaff090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000ceb92e0 (&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 5.5.0-rc2-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+0x55/0x96 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b0/0x1c7 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+0xa7c/0xf80 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: 30252 Comm: kdvb-ca-0:0 Not tainted 5.5.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:available_idle_cpu+0x8d/0x130 kernel/sched/core.c:4660 Code: 8b a3 a0 09 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 83 00 00 00 4c 3b a3 a8 09 00 00 74 07 <5b> 31 c0 5d 41 5c c3 48 8d 7b 38 48 b8 00 00 00 00 00 fc ff df 48 RSP: 0018:ffff8881db309c68 EFLAGS: 00000087 RAX: dffffc0000000000 RBX: ffff8881db234440 RCX: ffffffff8120da3d RDX: 1ffff1103b6469bd RSI: 0000000000000008 RDI: ffff8881db234de8 RBP: 0000000000000000 R08: ffff8881c4be8000 R09: ffffed103a73637e R10: ffffed103a73637d R11: ffff8881d39b1bef R12: ffff8881d8c38000 R13: ffffed103a73637c R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000210001ff CR3: 00000001c7e45000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: select_idle_cpu kernel/sched/fair.c:5867 [inline] select_idle_sibling kernel/sched/fair.c:5922 [inline] select_task_rq_fair+0x1c2f/0x26c0 kernel/sched/fair.c:6391 select_task_rq kernel/sched/core.c:2109 [inline] try_to_wake_up+0x41f/0x15d0 kernel/sched/core.c:2628 hrtimer_wakeup+0x43/0x60 kernel/time/hrtimer.c:1769 __run_hrtimer kernel/time/hrtimer.c:1517 [inline] __hrtimer_run_queues+0x303/0xc60 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x2e8/0x730 kernel/time/hrtimer.c:1641 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0xf5/0x500 arch/x86/kernel/apic/apic.c:1135 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 f2 c0 15 00 e8 bd 00 1b 00 41 56 9d e9 b6 fd ff ff e8 e0 c0 15 00 e8 ab 00 1b 00 41 56 9d 2a ff ff ff 0f 1f 00 55 48 89 f5 53 48 89 fb e8 c3 c0 15 00 49 RSP: 0018:ffff8881d4537bf8 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: 0000000000000200 RCX: 0000000000000006 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8881c4be884c RBP: ffff8881d4537c40 R08: ffff8881c4be8000 R09: fffffbfff11f1ebf R10: fffffbfff11f1ebe R11: ffffffff88f8f5f7 R12: 0000000000000026 R13: ffff8881d8c38000 R14: 0000000000000293 R15: 0000000000000000 vprintk_func+0x75/0x113 kernel/printk/printk_safe.c:386 printk+0xba/0xed kernel/printk/printk.c:2056 az6027_usb_in_op.cold+0x19/0x1e drivers/media/usb/dvb-usb/az6027.c:316 az6027_ci_poll_slot_status+0xc9/0x180 drivers/media/usb/dvb-usb/az6027.c:694 dvb_ca_en50221_check_camstatus+0x102/0x330 drivers/media/dvb-core/dvb_ca_en50221.c:234 dvb_ca_en50221_thread_state_machine drivers/media/dvb-core/dvb_ca_en50221.c:1128 [inline] dvb_ca_en50221_thread+0x26b/0x13e0 drivers/media/dvb-core/dvb_ca_en50221.c:1317 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352