INFO: task kworker/1:5:5785 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:23072 pid:5785 tgid:5785 ppid:2 task_flags:0x4288060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_timeout+0x1b2/0x280 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common+0x2e7/0x4c0 kernel/sched/completion.c:121
i2c_del_adapter+0x1d4/0x2d0 drivers/i2c/i2c-core-base.c:1840
em28xx_i2c_unregister+0x47/0x70 drivers/media/usb/em28xx/em28xx-i2c.c:1029
em28xx_release_resources+0xe0/0x1b0 drivers/media/usb/em28xx/em28xx-cards.c:3739
em28xx_usb_disconnect.cold+0x17d/0x253 drivers/media/usb/em28xx/em28xx-cards.c:4427
usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:618 [inline]
device_remove+0x12a/0x180 drivers/base/dd.c:610
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
device_del+0x376/0x9b0 drivers/base/core.c:3961
usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1478
usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2345
hub_port_connect drivers/usb/core/hub.c:5415 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5715 [inline]
port_event drivers/usb/core/hub.c:5879 [inline]
hub_event+0x1bb1/0x4420 drivers/usb/core/hub.c:5961
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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:
1 lock held by khungtaskd/31:
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by getty/5359:
#0: ffff8880370b90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5599:
#0: ffffffff8ebf3ca8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
6 locks held by kworker/1:5/5785:
#0: ffff88801fa97d40 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc900024cfd08 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
#2: ffff88802aa831d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#2: ffff88802aa831d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bb/0x4420 drivers/usb/core/hub.c:5907
#3: ffff88807e9781d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#3: ffff88807e9781d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336
#4: ffff88807f0861a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#4: ffff88807f0861a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
#4: ffff88807f0861a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369
#5: ffff88805291dcf0 (&dev->lock#4){+.+.}-{4:4}, at: em28xx_release_resources+0x71/0x1b0 drivers/media/usb/em28xx/em28xx-cards.c:3733
3 locks held by kworker/0:2H/5826:
4 locks held by udevd/5984:
#0: ffff8880551a73f8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183
#1: ffff888054f29c80 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:165
#2: ffff8880762fef08 (kn->active#27){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff8880762fef08 (kn->active#27){.+.+}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:166
#3: ffff88807e9781d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1109 [inline]
#3: ffff88807e9781d8 (&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: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
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:122
nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65
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+0x72b/0xd50 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: 5826 Comm: kworker/0:2H Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events_highpri snd_vmidi_output_work
RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:107 [inline]
RIP: 0010:raw_atomic_try_cmpxchg_acquire include/linux/atomic/atomic-arch-fallback.h:2170 [inline]
RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1302 [inline]
RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
RIP: 0010:do_raw_spin_lock+0x12c/0x260 kernel/locking/spinlock_debug.c:116
Code: 00 00 48 89 df be 04 00 00 00 c7 44 24 28 00 00 00 00 e8 87 b1 94 00 be 04 00 00 00 48 8d 7c 24 28 e8 78 b1 94 00 8b 44 24 28 01 00 00 00 89 44 24 04 f0 0f b1 13 0f 85 93 00 00 00 48 89 ea
RSP: 0018:ffffc900044e76c8 EFLAGS: 00000097
RAX: 0000000000000000 RBX: ffff8880546c0070 RCX: ffffffff81e65668
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc900044e76f0
RBP: ffff8880546c0078 R08: 0000000000000001 R09: fffff5200089cede
R10: 0000000000000003 R11: 0000000000000000 R12: 1ffff9200089ceda
R13: ffff8880546c0080 R14: ffff8880546c0070 R15: ffff8880546c0018
FS: 0000000000000000(0000) GS:ffff888123dec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000003000 CR3: 000000007628a000 CR4: 00000000003526f0
Call Trace:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:166
class_spinlock_irqsave_constructor include/linux/spinlock.h:619 [inline]
snd_seq_oss_readq_put_timestamp+0x7e/0x260 sound/core/seq/oss/seq_oss_readq.c:224
send_synth_event sound/core/seq/oss/seq_oss_midi.c:559 [inline]
snd_seq_oss_midi_input+0x7c4/0xa30 sound/core/seq/oss/seq_oss_midi.c:499
snd_seq_oss_event_input+0x194/0x250 sound/core/seq/oss/seq_oss_event.c:429
__snd_seq_deliver_single_event sound/core/seq/seq_clientmgr.c:626 [inline]
__snd_seq_deliver_single_event+0x127/0x1c0 sound/core/seq/seq_clientmgr.c:613
_snd_seq_deliver_single_event sound/core/seq/seq_clientmgr.c:672 [inline]
snd_seq_deliver_single_event+0x31f/0x8c0 sound/core/seq/seq_clientmgr.c:687
__deliver_to_subscribers sound/core/seq/seq_clientmgr.c:735 [inline]
deliver_to_subscribers sound/core/seq/seq_clientmgr.c:763 [inline]
snd_seq_deliver_event+0x2c1/0x860 sound/core/seq/seq_clientmgr.c:813
snd_seq_kernel_client_dispatch+0x16f/0x1b0 sound/core/seq/seq_clientmgr.c:2439
snd_vmidi_output_work+0x1d1/0x390 sound/core/seq/seq_virmidi.c:157
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245