INFO: task kworker/0:4:5226 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4 state:D
stack:21736 pid:5226 tgid:5226 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/0:0/9:
#0:
ffff888105e90540
(
(wq_completion)usb_hub_wq
){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277
#1:
ffffc9000009fd18
(
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278
#2:
ffff88810c34b1d8
(
&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:
ffff88811aa601d8
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
#4:
ffff88811ba0e1a0
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
#5:
ffffffff8aa2d220
(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
1 lock held by khungtaskd/30:
#0:
ffffffff896ddaa0
(
rcu_read_lock
){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
6 locks held by kworker/0:2/1123:
#0: ffff888105e90540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277
#1:
ffffc900032dfd18
(
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278
#2: ffff88810bf331d8 (&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:
ffff8881340ed1d8
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
#4:
ffff888141a941a0 (&dev->mutex){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
#5: ffffffff8aa2d220 (register_mutex#3){+.+.}-{4:4}
, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952
2 locks held by getty/2923:
#0:
ffff888115d3b0a0
(
&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/5213:
#0:
ffff8881367adab8
(
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1: ffff88811d81d880
(
&of->mutex
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
#2:
ffff888136231968
(
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:
ffff88811aa601d8
(
&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
6 locks held by kworker/0:4/5226:
#0:
ffff888105e90540
(
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277
#1:
ffffc9000221fd18
(
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278
#2:
ffff88810c74b1d8
(
&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:
ffff8881231e51d8
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
#4:
ffff8881127171a0
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
#5:
ffffffff8aa2d220
(
register_mutex
#3
){+.+.}-{4:4}
, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952
4 locks held by udevd/5231:
#0:
ffff888115874758
(
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1:
ffff88810ba91080
(
&of->mutex
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
#2:
ffff8881364dea58
(
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:
ffff8881146791d8
(
&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
6 locks held by kworker/0:6/5585:
#0:
ffff888105e90540
(
(wq_completion)usb_hub_wq
){+.+.}-{0:0}
, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277
#1:
ffffc90003317d18
(
(work_completion)(&hub->events)
){+.+.}-{0:0}
, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278
#2:
ffff88810bfdb1d8
(
&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:
ffff8881146791d8
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
#4:
ffff8881411d51a0
(
&dev->mutex
){....}-{4:4}
, at: device_lock include/linux/device.h:1040 [inline]
, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076
#5:
ffffffff8aa2d220
(
register_mutex
#3
){+.+.}-{4:4}
, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952
4 locks held by udevd/6623:
#0:
ffff888134fe6e18
(
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1:
ffff88811c015c80
(
&of->mutex
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
#2:
ffff88813db450f8
(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:
ffff888140f891d8
(
&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/6997:
#0:
ffff88811464f098
(
&p->lock
){+.+.}-{4:4}
, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1:
ffff88811a984880
(
&of->mutex
){+.+.}-{4:4}
, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172
#2:
ffff888140048b48
(
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:
ffff8881340ed1d8 (&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
11 locks held by kworker/1:8/11571:
=============================================
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 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: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: 7081 Comm: kworker/1:7 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:find_held_lock+0x6f/0x80 kernel/locking/lockdep.c:5373
Code: 57 35 e1 05 85 c0 75 19 83 ed 01 48 83 eb 28 83 fd ff 74 0b 0f b6 43 49 32 43 21 a8 60 74 da 31 db 41 89 6d 00 48 89 d8 5b 5d <41> 5c 41 5d 41 5e c3 cc cc cc cc 66 0f 1f 44 00 00 90 90 90 90 90
RSP: 0018:ffffc900001a8948 EFLAGS: 00000002
RAX: ffff88811e7f2980 RBX: ffffffff896ddaa0 RCX: ffffc900001a8974
RDX: 0000000000000004 RSI: ffffffff896ddaa0 RDI: ffff88811e7f2980
RBP: ffffffff816fcd5e R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000010fb0 R12: ffffffff896ddaa0
R13: ffffc900001a8974 R14: 0000000000000004 R15: 0000000000000004
FS: 0000000000000000(0000) GS:ffff88826878b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555ed68908 CR3: 00000001170f6000 CR4: 00000000003506f0
Call Trace:
__lock_release kernel/locking/lockdep.c:5535 [inline]
lock_release kernel/locking/lockdep.c:5889 [inline]
lock_release+0xdb/0x310 kernel/locking/lockdep.c:5875
rcu_lock_release include/linux/rcupdate.h:310 [inline]
rcu_read_unlock include/linux/rcupdate.h:869 [inline]
class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
unwind_next_frame+0x3c3/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x43/0x70 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2689 [inline]
slab_free mm/slub.c:6246 [inline]
kmem_cache_free+0x108/0x660 mm/slub.c:6373
rcu_do_batch kernel/rcu/tree.c:2617 [inline]
rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2869
handle_softirqs+0x1dd/0x9e0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x160/0x210 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:console_trylock_spinning kernel/printk/printk.c:2039 [inline]
RIP: 0010:vprintk_emit+0x553/0x6b0 kernel/printk/printk.c:2478
Code: 00 4d 85 ed 0f 85 1b 01 00 00 e8 d8 8b 20 00 9c 5d 81 e5 00 02 00 00 31 ff 48 89 ee e8 a6 86 20 00 48 85 ed 0f 85 27 01 00 00 b8 8b 20 00 45 31 c9 41 b8 01 00 00 00 31 c9 48 8d 05 00 00 00
RSP: 0018:ffffc9001560f9d0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000017 RCX: ffffffff8192337a
RDX: ffff88811e7f1dc0 RSI: ffffffff81923384 RDI: ffff88811e7f1dc0
RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff92002ac1f3c
R13: 0000000000000200 R14: ffff8881026f0000 R15: ffffc9001560fa98
_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+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