INFO: task kworker/1:2:1123 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:2 state:D stack:21888 pid:1123 tgid:1123 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: usb_hub_wq hub_event Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0xf89/0x4840 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7282 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7339 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820 class_mutex_constructor include/linux/mutex.h:253 [inline] usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:631 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:709 __driver_probe_device+0x22e/0x480 drivers/base/dd.c:871 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:901 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1029 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1101 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1156 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x1210/0x1950 drivers/base/core.c:3706 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291 call_driver_probe drivers/base/dd.c:631 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:709 __driver_probe_device+0x22e/0x480 drivers/base/dd.c:871 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:901 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1029 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1101 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1156 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x1210/0x1950 drivers/base/core.c:3706 usb_new_device.cold+0x685/0x115c drivers/usb/core/hub.c:2695 hub_port_connect drivers/usb/core/hub.c:5567 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x314d/0x4af0 drivers/usb/core/hub.c:5953 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 6 locks held by kworker/1:1/28: #0: ffff8881062ad540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc900001e7d18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810c7631d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88810c7631d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88813dba01d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff88813dba01d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff88813dba21a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88813dba21a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa1d5e0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa1d5e0 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 1 lock held by khungtaskd/30: #0: ffffffff896ddaa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff896ddaa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff896ddaa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 6 locks held by kworker/1:2/1123: #0: ffff8881062ad540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc90002f6fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810c3fb1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88810c3fb1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88811d9e21d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff88811d9e21d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff88811de4b1a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88811de4b1a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa1d5e0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa1d5e0 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 1 lock held by klogd/2841: #0: ffff8881f57396e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:652 [inline] #0: ffff8881f57396e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock kernel/sched/sched.h:1624 [inline] #0: ffff8881f57396e0 (&rq->__lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1968 [inline] #0: ffff8881f57396e0 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0x2bc/0x4840 kernel/sched/core.c:7063 2 locks held by getty/2915: #0: ffff888112b350a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000452e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14f0 drivers/tty/n_tty.c:2211 4 locks held by udevd/5196: #0: ffff888118cef758 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88810871cc80 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888136a132d8 (kn->active#24){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888136a132d8 (kn->active#24){.+.+}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88811d9e51d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff88811d9e51d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/5205: #0: ffff8881351f1f38 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff888136940480 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff8881097e2968 (kn->active#24){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8881097e2968 (kn->active#24){.+.+}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88813c50a1d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff88813c50a1d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 6 locks held by kworker/0:2/5207: #0: ffff8881062ad540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc900022efd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810c3511d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88810c3511d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88813ca801d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff88813ca801d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff88811b3451a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88811b3451a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa1d5e0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa1d5e0 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 6 locks held by kworker/1:3/5227: 4 locks held by udevd/5245: #0: ffff888135d80cf8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff8881229fa880 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888135568a58 (kn->active#24){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888135568a58 (kn->active#24){.+.+}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88813ca801d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff88813ca801d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/5247: #0: ffff888113fa23f8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff888134749080 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888113711d28 (kn->active#24){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888113711d28 (kn->active#24){.+.+}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88813dba01d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff88813dba01d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 6 locks held by kworker/0:5/5361: #0: ffff8881062ad540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc90002dffd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810c3e31d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88810c3e31d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88813c50a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff88813c50a1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff88813c54d1a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88813c54d1a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa1d5e0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa1d5e0 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xcb1/0x1030 kernel/hung_task.c:561 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158 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: 5227 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: usb_hub_wq hub_event RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x17/0x70 kernel/kcov.c:217 Code: 01 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 8b 05 85 1c 45 0b 48 8b 34 24 65 48 8b 15 61 1c 45 0b 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 11 bc RSP: 0018:ffffc90002bceca8 EFLAGS: 00000206 RAX: 0000000080000000 RBX: ffff88811d862007 RCX: ffffffff862f69cf RDX: ffff888118fd9dc0 RSI: ffffffff862f69de RDI: ffff888118fd9dc0 RBP: dffffc0000000000 R08: 0000000000000005 R09: 0000000000000002 R10: 00000000000007fb R11: ffffffff81592b9a R12: 00000000000007fb R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000006 FS: 0000000000000000(0000) GS:ffff8882687a9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000123446000 CR4: 00000000003506f0 Call Trace: convert_chmap_v3 sound/usb/stream.c:354 [inline] snd_usb_get_audioformat_uac3 sound/usb/stream.c:1040 [inline] __snd_usb_parse_audio_interface+0x1d4e/0x4710 sound/usb/stream.c:1215 snd_usb_parse_audio_interface+0x81/0x110 sound/usb/stream.c:1290 snd_usb_create_stream.isra.0+0x241/0x4d0 sound/usb/card.c:319 snd_usb_create_streams sound/usb/card.c:440 [inline] usb_audio_probe+0x1119/0x3b60 sound/usb/card.c:1032 usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:631 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:709 __driver_probe_device+0x22e/0x480 drivers/base/dd.c:871 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:901 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1029 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1101 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1156 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x1210/0x1950 drivers/base/core.c:3706 usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268 usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250 usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291 call_driver_probe drivers/base/dd.c:631 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:709 __driver_probe_device+0x22e/0x480 drivers/base/dd.c:871 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:901 __device_attach_driver+0x1df/0x340 drivers/base/dd.c:1029 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1101 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1156 bus_probe_device+0x64/0x160 drivers/base/bus.c:613 device_add+0x1210/0x1950 drivers/base/core.c:3706 usb_new_device.cold+0x685/0x115c drivers/usb/core/hub.c:2695 hub_port_connect drivers/usb/core/hub.c:5567 [inline] hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] port_event drivers/usb/core/hub.c:5871 [inline] hub_event+0x314d/0x4af0 drivers/usb/core/hub.c:5953 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3302 process_scheduled_works kernel/workqueue.c:3385 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3466 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x69a/0xc80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245