INFO: task kworker/0:2:2358 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:2 state:D stack:21528 pid:2358 tgid:2358 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:712 [inline] __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:806 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: ffff888105ea8540 ((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: ffff88810c7041d8 (&dev->mutex ){....}-{4:4} , at: device_lock include/linux/device.h:1040 [inline] , at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff888118d921d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff888118d921d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff88811bdb61a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88811bdb61a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa2ddc0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa2ddc0 (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/0:2/2358: #0: ffff888105ea8540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc900063dfd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810cb6c1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] ffff88810cb6c1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88813a22b1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff88813a22b1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff88812f9601a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88812f9601a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa2ddc0 ( register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 2 locks held by getty/2932: #0: ffff888115b410a0 (&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 6 locks held by kworker/0:4/5241: #0: ffff888105ea8540 ( (wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc9000385fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810cb141d8 ( &dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] &dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff888128e151d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff888128e151d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff8881151c81a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff8881151c81a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa2ddc0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa2ddc0 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 2 locks held by kworker/1:5/12214: #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 #1: ffffc90001fcfd18 ((work_completion)(&(&ssp->srcu_sup->work)->work)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 6 locks held by kworker/1:2/14893: 6 locks held by kworker/0:7/15484: #0: ffff888105ea8540 ((wq_completion)usb_hub_wq ){+.+.}-{0:0} , at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc90016f47d18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810c75c1d8 (&dev->mutex){....}-{4:4} , at: device_lock include/linux/device.h:1040 [inline] , at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff888133e741d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff888133e741d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff88813b63c1a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88813b63c1a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa2ddc0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa2ddc0 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 4 locks held by udevd/18193: #0: ffff888121121638 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff888110348080 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888130b60d28 (kn->active#26){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888130b60d28 (kn->active#26){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88813a22b1d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff88813a22b1d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/18220: #0: ffff88813e8c1758 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88811f174480 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff8881310cd5a8 (kn->active#26){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8881310cd5a8 (kn->active#26){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff888133e851d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff888133e851d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/18270: #0: ffff8881332cd518 ( &p->lock ){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88811a5ef080 ( &of->mutex #2 ){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff888120034878 (kn->active#26){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] (kn->active#26){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff888133e741d8 ( &dev->mutex){....}-{4:4} , at: device_lock_interruptible include/linux/device.h:1045 [inline] , at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/20106: #0: ffff88810dbb4878 ( &p->lock){+.+.}-{4:4} , at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff888133c76880 (&of->mutex #2 ){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff8881146fe698 (kn->active #26){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #26){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff888128e151d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff888128e151d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/21055: #0: ffff8881153b22d8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88811a2e2c80 (&of->mutex #2 ){+.+.}-{4:4} , at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff8881143fd2d8 ( kn->active #26 ){++++}-{0:0} , at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] , at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff888118d921d8 ( &dev->mutex ){....}-{4:4} , at: device_lock_interruptible include/linux/device.h:1045 [inline] , at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 ============================================= 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: 14893 Comm: kworker/1:2 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:io_serial_in+0x87/0xb0 drivers/tty/serial/8250/8250_port.c:402 Code: 34 8f fe 48 8d 7d 40 44 89 e1 48 b8 00 00 00 00 00 fc ff df 48 89 fa d3 e3 48 c1 ea 03 80 3c 02 00 75 1a 66 03 5d 40 89 da ec <5b> 0f b6 c0 5d 41 5c c3 cc cc cc cc e8 98 d6 f4 fe eb a2 e8 21 d7 RSP: 0018:ffffc90015fd62b8 EFLAGS: 00000002 RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: ffffffff83238b40 RDI: ffffffff941fad40 RBP: ffffffff941fad00 R08: 0000000000000001 R09: 000000000000001f R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000020 R14: fffffbfff283f5fa R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888268787000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556d43c908 CR3: 00000001235a8000 CR4: 00000000003506f0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:128 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline] wait_for_lsr+0x13a/0x210 drivers/tty/serial/8250/8250_port.c:1970 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3207 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3272 [inline] serial8250_console_write+0xdb9/0x1900 drivers/tty/serial/8250/8250_port.c:3357 console_emit_next_record kernel/printk/printk.c:3183 [inline] console_flush_one_record+0x790/0xe50 kernel/printk/printk.c:3269 console_flush_all kernel/printk/printk.c:3343 [inline] __console_flush_and_unlock kernel/printk/printk.c:3373 [inline] console_unlock+0x103/0x260 kernel/printk/printk.c:3413 vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479 dev_vprintk_emit+0x394/0x3e0 drivers/base/core.c:4930 dev_printk_emit+0xd2/0x10d drivers/base/core.c:4941 __dev_printk+0xcb/0x100 drivers/base/core.c:4953 _dev_err+0xef/0x127 drivers/base/core.c:4996 parse_uac2_sample_rate_range.cold+0xff/0x134 sound/usb/format.c:472 parse_audio_format_rates_v2v3+0x2fe/0xf70 sound/usb/format.c:693 parse_audio_format_ii sound/usb/format.c:851 [inline] snd_usb_parse_audio_format.cold+0x48c/0x4cc sound/usb/format.c:872 snd_usb_get_audioformat_uac12 sound/usb/stream.c:864 [inline] __snd_usb_parse_audio_interface+0xa85/0x4710 sound/usb/stream.c:1209 snd_usb_parse_audio_interface+0x81/0x110 sound/usb/stream.c:1290 create_standard_audio_quirk+0x6b/0x120 sound/usb/quirks.c:104 snd_usb_create_quirk sound/usb/quirks.c:544 [inline] create_composite_quirk+0x257/0x510 sound/usb/quirks.c:52 snd_usb_create_quirk+0xad/0xf0 sound/usb/quirks.c:544 usb_audio_probe+0x969/0x3b60 sound/usb/card.c:1025 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