INFO: task kworker/0:4:4402 blocked for more than 143 seconds. Not tainted 5.5.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/0:4 D23232 4402 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+0x17a/0x780 kernel/kthread.c:559 dvb_ca_en50221_release+0x91/0x1d0 drivers/media/dvb-core/dvb_ca_en50221.c:1934 tt3650_ci_uninit drivers/media/usb/dvb-usb/pctv452e.c:364 [inline] pctv452e_usb_disconnect+0xb0/0xf0 drivers/media/usb/dvb-usb/pctv452e.c:1061 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+0x2eb/0x5a0 drivers/base/bus.c:532 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:2201 hub_port_connect drivers/usb/core/hub.c:5036 [inline] hub_port_connect_change drivers/usb/core/hub.c:5325 [inline] port_event drivers/usb/core/hub.c:5471 [inline] hub_event+0x1a1d/0x4300 drivers/usb/core/hub.c:5553 process_one_work+0x945/0x15c0 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: 2 locks held by kworker/0:1/12: #0: ffff8881da028d28 ((wq_completion)events){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881da028d28 ((wq_completion)events){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881da028d28 ((wq_completion)events){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881da028d28 ((wq_completion)events){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881da028d28 ((wq_completion)events){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881da028d28 ((wq_completion)events){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881da028d28 ((wq_completion)events){+.+.}, at: process_one_work+0x827/0x15c0 kernel/workqueue.c:2235 #1: ffff8881da227dd0 (console_work){+.+.}, at: process_one_work+0x85b/0x15c0 kernel/workqueue.c:2239 1 lock held by khungtaskd/22: #0: ffffffff871055a0 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x264 kernel/locking/lockdep.c:5331 1 lock held by rsyslogd/1681: #0: ffff8881cf441c60 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:801 2 locks held by getty/1773: #0: ffff8881cea97090 (&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/1774: #0: ffff8881ce699090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900004652e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by getty/1775: #0: ffff8881ce9dd090 (&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/1776: #0: ffff8881ce5cd090 (&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/1778: #0: ffff8881cea90090 (&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/0:4/4402: #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x827/0x15c0 kernel/workqueue.c:2235 #1: ffff8881c901fdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85b/0x15c0 kernel/workqueue.c:2239 #2: ffff8881d4d70200 (&dev->mutex){....}, at: device_lock include/linux/device.h:1493 [inline] #2: ffff8881d4d70200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5499 #3: ffff8881cd4f0200 (&dev->mutex){....}, at: device_lock include/linux/device.h:1493 [inline] #3: ffff8881cd4f0200 (&dev->mutex){....}, at: usb_disconnect+0x91/0x900 drivers/usb/core/hub.c:2192 #4: ffff8881ad4d2190 (&dev->mutex){....}, at: device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1162 2 locks held by getty/9942: #0: ffff8881ad917090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9000e54c2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 5 locks held by kworker/0:8/18817: 3 locks held by kworker/1:0/23768: #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff8881d88fcd28 ((wq_completion)usb_hub_wq){+.+.}, at: process_one_work+0x827/0x15c0 kernel/workqueue.c:2235 #1: ffff8881abe9fdd0 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x85b/0x15c0 kernel/workqueue.c:2239 #2: ffff8881d4d39200 (&dev->mutex){....}, at: device_lock include/linux/device.h:1493 [inline] #2: ffff8881d4d39200 (&dev->mutex){....}, at: hub_event+0x1be/0x4300 drivers/usb/core/hub.c:5499 4 locks held by kdvb-ca-0:0/4540: 2 locks held by getty/4765: #0: ffff8881d41b4090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc9001104c2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x21d/0x1b30 drivers/tty/n_tty.c:2156 6 locks held by kworker/u4:2/5939: #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+0x827/0x15c0 kernel/workqueue.c:2235 #1: ffff8881cb0afdd0 ((work_completion)(&buf->work)){+.+.}, at: process_one_work+0x85b/0x15c0 kernel/workqueue.c:2239 #2: ffff8881ce69b0a8 (&buf->lock){+.+.}, at: flush_to_ldisc+0x3e/0x390 drivers/tty/tty_buffer.c:505 #3: ffff8881d41b4090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:288 #4: ffff8881d41b42a0 (&tty->termios_rwsem){++++}, at: n_tty_receive_buf_common+0x87/0x2ac0 drivers/tty/n_tty.c:1705 #5: ffffc9001104c360 (&ldata->output_lock){+.+.}, at: flush_echoes drivers/tty/n_tty.c:827 [inline] #5: ffffc9001104c360 (&ldata->output_lock){+.+.}, at: __receive_buf drivers/tty/n_tty.c:1648 [inline] #5: ffffc9001104c360 (&ldata->output_lock){+.+.}, at: n_tty_receive_buf_common+0xc26/0x2ac0 drivers/tty/n_tty.c:1742 4 locks held by syz-executor.0/6441: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 22 Comm: khungtaskd Not tainted 5.5.0-rc7-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: 4540 Comm: kdvb-ca-0:0 Not tainted 5.5.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:expire_timers kernel/time/timer.c:1450 [inline] RIP: 0010:__run_timers kernel/time/timer.c:1773 [inline] RIP: 0010:__run_timers kernel/time/timer.c:1740 [inline] RIP: 0010:run_timer_softirq+0x5f9/0x1500 kernel/time/timer.c:1786 Code: 00 8b 74 24 40 85 f6 0f 85 ef fd ff ff e8 6f ed 0e 00 4c 89 ff e8 17 a3 5d 04 48 8b 54 24 10 48 89 de 48 89 ef e8 b7 c7 ff ff <48> 8b 44 24 08 80 38 00 0f 85 dd 0c 00 00 4c 89 ff 49 c7 47 38 00 RSP: 0018:ffff8881db309e10 EFLAGS: 00000286 RAX: 0000000000000000 RBX: ffffffff812fba00 RCX: ffffffff812fee16 RDX: 0000000000000100 RSI: ffffffff812fee72 RDI: 0000000000000004 RBP: ffff8881abe9f928 R08: ffff8881ab54b100 R09: fffffbfff0fc3ab1 R10: fffffbfff0fc3ab0 R11: ffffffff87e1d587 R12: ffff8881db309e80 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881db325f40 FS: 0000000000000000(0000) GS:ffff8881db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000001b0681000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __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:536 [inline] smp_apic_timer_interrupt+0x141/0x540 arch/x86/kernel/apic/apic.c:1137 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 82 d6 15 00 e8 ad 1a 1b 00 41 56 9d e9 b6 fd ff ff e8 70 d6 15 00 e8 9b 1a 1b 00 41 56 9d 2a ff ff ff 0f 1f 00 55 48 89 f5 53 48 89 fb e8 53 d6 15 00 49 RSP: 0018:ffff8881b2f67b60 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000007 RBX: 0000000000000200 RCX: 0000000000000006 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8881ab54b94c RBP: ffff8881b2f67ba8 R08: ffff8881ab54b100 R09: fffffbfff1269cbd R10: fffffbfff1269cbc R11: ffffffff8934e5e7 R12: 000000000000002d R13: ffff8881da24e200 R14: 0000000000000293 R15: 0000000000000000 vprintk_func+0x75/0x113 kernel/printk/printk_safe.c:386 printk+0xba/0xed kernel/printk/printk.c:2056 tt3650_ci_msg.cold+0x30/0x3e drivers/media/usb/dvb-usb/pctv452e.c:141 tt3650_ci_msg_locked+0x83/0xb0 drivers/media/usb/dvb-usb/pctv452e.c:157 tt3650_ci_poll_slot_status+0x90/0x110 drivers/media/usb/dvb-usb/pctv452e.c:333 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