INFO: task kworker/1:4:5251 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4 state:D stack:22520 pid:5251 tgid:5251 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0xeb1/0x4220 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7008
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
class_mutex_constructor include/linux/mutex.h:253 [inline]
usb_audio_probe+0x38f/0x3a90 sound/usb/card.c:950
usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:643 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:721
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:863
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:893
__device_attach_driver+0x1df/0x340 drivers/base/dd.c:1021
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1093
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1148
bus_probe_device+0x64/0x160 drivers/base/bus.c:613
device_add+0x11d9/0x1950 drivers/base/core.c:3691
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:643 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:721
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:863
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:893
__device_attach_driver+0x1df/0x340 drivers/base/dd.c:1021
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1093
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1148
bus_probe_device+0x64/0x160 drivers/base/bus.c:613
device_add+0x11d9/0x1950 drivers/base/core.c:3691
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+0xa23/0x19a0 kernel/workqueue.c:3276
process_scheduled_works kernel/workqueue.c:3359 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x6c3/0xcb0 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/1:0/23:
#0:
ffff888105ec9948
(
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1:
ffffc9000018fd18
((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
#2:
ffff88810b3a91e0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
ffff88810b3a91e0 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
#3:
ffff88811b5951e0
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:949 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
#4: ffff888119e241a8 (&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:949 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
#5:
ffffffff8aa21188 (register_mutex#3){+.+.}-{4:4}
, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
, at: usb_audio_probe+0x38f/0x3a90 sound/usb/card.c:950
1 lock held by khungtaskd/30:
#0: ffffffff896de760 (rcu_read_lock){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
6 locks held by kworker/1:2/746:
#0:
ffff888105ec9948
(
(wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1:
ffffc9000261fd18
((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
#2:
ffff88810b7891e0
(
&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
#3:
ffff8881213321e0
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:949 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
#4:
ffff8881213001a8
(
&dev->mutex
){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
#5:
ffffffff8aa21188
(
register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x38f/0x3a90 sound/usb/card.c:950
2 locks held by getty/2918:
#0: ffff888115f930a0 (&tty->ldisc_sem){++++}-{0:0}
, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1:
ffffc900000432f0
(
&ldata->atomic_read_lock
){+.+.}-{4:4}, at: n_tty_read+0x419/0x1500 drivers/tty/n_tty.c:2211
6 locks held by kworker/0:3/5215:
#0:
ffff888105ec9948 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1:
ffffc90002b5fd18
(
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
#2:
ffff88810b3c11e0
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:949 [inline]
, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
#3:
ffff8881236e41e0
(&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
(&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
#4: ffff88812159c1a8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
#4: ffff88812159c1a8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
#5: ffffffff8aa21188 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#5: ffffffff8aa21188 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x38f/0x3a90 sound/usb/card.c:950
4 locks held by udevd/5235:
#0:
ffff88810bb4b0a0
(&p->lock){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1: ffff88810635e088 (&of->mutex#2){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
#2:
ffff88813584c4b8
(kn->active#23){++++}-{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:
ffff8881213321e0
(
&dev->mutex
){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:954 [inline]
){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
6 locks held by kworker/1:4/5251:
#0:
ffff888105ec9948
(
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x1310/0x19a0 kernel/workqueue.c:3251
#1:
ffffc9000310fd18
(
(work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x19a0 kernel/workqueue.c:3252
#2:
ffff88810b3591e0
(&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:949 [inline]
, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899
#3:
ffff88811c4e31e0
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:949 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
#4:
ffff8881353541a8
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:949 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1068
#5:
ffffffff8aa21188
(register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
(register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x38f/0x3a90 sound/usb/card.c:950
4 locks held by udevd/5366:
#0:
ffff888115e582f0
(
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1: ffff8881194c9888 (&of->mutex#2){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
#2: ffff8881139f21e8 (kn->active#23){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff8881139f21e8 (kn->active#23){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
#3: ffff88811b5951e0 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:954 [inline]
#3: ffff88811b5951e0 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
4 locks held by udevd/5473:
#0: ffff88811a6872f0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1: ffff88811bda6c88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
#2: ffff88813387dc38 (kn->active#23){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
#2: ffff88813387dc38 (kn->active#23){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
#3: ffff888134e9c1e0 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:954 [inline]
#3: ffff888134e9c1e0 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
6 locks held by kworker/0:7/5510:
4 locks held by udevd/5688:
#0: ffff88811520b540 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1: ffff88811e228088 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
#2: ffff8881196f4008 (kn->active#23
){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173
#3: ffff88811c4e31e0 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:954 [inline]
#3: ffff88811c4e31e0 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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:161 [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:346 [inline]
watchdog+0xd25/0x1050 kernel/hung_task.c:515
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5221 Comm: kworker/0:4 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events legacy_dvb_usb_read_remote_control
RIP: 0010:memchr+0x2e/0x80 lib/string.c:809
Code: 55 48 01 fa 48 bd 00 00 00 00 00 fc ff df 53 48 83 ec 18 eb 26 48 89 f8 48 89 f9 48 8d 5f 01 48 c1 e8 03 83 e1 07 0f b6 04 28 <38> c8 7f 04 84 c0 75 29 40 3a 73 ff 74 15 48 89 df 48 39 d7 75 d5
RSP: 0018:ffffc90002bef4f0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff93ff8709 RCX: 0000000000000000
RDX: ffffffff93ff8739 RSI: 000000000000000a RDI: ffffffff93ff8708
RBP: dffffc0000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 000000007fffffff R11: 00000000001d3354 R12: ffffffff93ff86e0
R13: 0000000000000000 R14: ffffc90002bef688 R15: ffffc90002bef6c8
FS: 0000000000000000(0000) GS:ffff8882686c9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556cf95908 CR3: 0000000116b3c000 CR4: 00000000003506f0
Call Trace:
memchr include/linux/fortify-string.h:737 [inline]
record_print_text+0x239/0x3c0 kernel/printk/printk.c:1443
printk_get_next_message+0x2d1/0x6c0 kernel/printk/printk.c:3072
console_emit_next_record kernel/printk/printk.c:3137 [inline]
console_flush_one_record+0x67c/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
_printk+0xcf/0x110 kernel/printk/printk.c:2504
m920x_read drivers/media/usb/dvb-usb/m920x.c:40 [inline]
m920x_rc_query.cold+0x2b/0x30 drivers/media/usb/dvb-usb/m920x.c:188
legacy_dvb_usb_read_remote_control+0x10c/0x4f0 drivers/media/usb/dvb-usb/dvb-usb-remote.c:123
process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
process_scheduled_works kernel/workqueue.c:3359 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245