INFO: task kworker/1:5:5993 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:5 state:D stack:17736 pid:5993 tgid:5993 ppid:2 task_flags:0x4288060 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common kernel/sched/completion.c:121 [inline] wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153 i2c_del_adapter+0x581/0x6e0 drivers/i2c/i2c-core-base.c:1817 ttusb_disconnect+0x204/0x340 drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:1737 usb_unbind_interface+0x26b/0x910 drivers/usb/core/driver.c:458 device_remove drivers/base/dd.c:571 [inline] __device_release_driver drivers/base/dd.c:1274 [inline] device_release_driver_internal+0x4d9/0x800 drivers/base/dd.c:1297 bus_remove_device+0x34d/0x410 drivers/base/bus.c:579 device_del+0x511/0x8e0 drivers/base/core.c:3878 usb_disable_device+0x3e9/0x8a0 drivers/usb/core/message.c:1418 usb_disconnect+0x330/0x950 drivers/usb/core/hub.c:2344 hub_port_connect drivers/usb/core/hub.c:5406 [inline] hub_port_connect_change drivers/usb/core/hub.c:5706 [inline] port_event drivers/usb/core/hub.c:5870 [inline] hub_event+0x1cf5/0x4a20 drivers/usb/core/hub.c:5952 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 7 locks held by kworker/1:1/44: 2 locks held by getty/5629: #0: ffff8880339ab0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900036c32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222 5 locks held by kworker/1:5/5993: #0: ffff88801dafd148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801dafd148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc9000ab37bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc9000ab37bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff888027cc4198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] #2: ffff888027cc4198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898 #3: ffff888027d80198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] #3: ffff888027d80198 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0xf8/0x950 drivers/usb/core/hub.c:2335 #4: ffff88805540c160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] #4: ffff88805540c160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1096 [inline] #4: ffff88805540c160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x800 drivers/base/dd.c:1294 2 locks held by syz.4.3551/20386: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5896 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:arch_exit_work+0x0/0x50 arch/x86/include/asm/entry-common.h:49 Code: 4f 00 90 0f 0b 90 90 90 c3 cc cc cc cc cc 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <53> 48 89 fb f7 c3 00 08 00 00 75 17 f7 c3 00 00 40 00 75 1c f7 c3 RSP: 0018:ffffc9000b0a7ed8 EFLAGS: 00000006 RAX: ffffffff81688a16 RBX: 0000000000004000 RCX: ffff88802b540000 RDX: 0000000000000000 RSI: 0000000000004000 RDI: 0000000000004000 RBP: ffffc9000b0a7f48 R08: ffff88802b540007 R09: 1ffff110056a8000 R10: dffffc0000000000 R11: ffffed10056a8001 R12: 0000000000000000 R13: 00000000000000e6 R14: ffffc9000b0a7f58 R15: ffff88802b540000 FS: 000055558ab66500(0000) GS:ffff888125d18000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555577e675c8 CR3: 000000007ad9c000 CR4: 00000000003526f0 Call Trace: arch_exit_to_user_mode_prepare+0x2c/0x50 arch/x86/include/asm/entry-common.h:66 exit_to_user_mode_prepare include/linux/irq-entry-common.h:227 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x177/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3ae55c1463 Code: 1f 84 00 00 00 00 00 83 ff 03 74 7b 83 ff 02 b8 fa ff ff ff 49 89 ca 0f 44 f8 80 3d fe 70 1d 00 00 74 14 b8 e6 00 00 00 0f 05 d8 c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec 28 48 89 54 24 10 RSP: 002b:00007ffcc9028808 EFLAGS: 00000202 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f3ae55c1463 RDX: 00007ffcc9028820 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 000000002efd8c53 R09: 7fffffffffffffff R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffcc9028c70 R13: 0000000000000004 R14: 00007ffcc902885c R15: 00007ffcc90288f0