syzbot

INFO: task kworker/0:7:5960 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:7     state:D
 stack:21672 pid:5960  tgid:5960  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7188
 __schedule_loop kernel/sched/core.c:7267 [inline]
 schedule+0x164/0x360 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+0x7f5/0x1550 kernel/locking/mutex.c:806
 class_mutex_constructor include/linux/mutex.h:253 [inline]
 usb_audio_probe+0x63a/0x2380 sound/usb/card.c:952
 usb_probe_interface+0x659/0xc70 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:709
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:851
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:881
 __device_attach_driver+0x279/0x430 drivers/base/dd.c:1009
 bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c5/0x450 drivers/base/dd.c:1081
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1136
 bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
 device_add+0x7b6/0xb70 drivers/base/core.c:3691
 usb_set_configuration+0x1a87/0x2110 drivers/usb/core/message.c:2266
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
 usb_probe_device+0x1c4/0x3b0 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:709
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:851
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:881
 __device_attach_driver+0x279/0x430 drivers/base/dd.c:1009
 bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c5/0x450 drivers/base/dd.c:1081
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1136
 bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
 device_add+0x7b6/0xb70 drivers/base/core.c:3691
 usb_new_device+0xa08/0x16f0 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+0x2a1c/0x4f30 drivers/usb/core/hub.c:5953
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Showing all locks held in the system:
3 locks held by kworker/u8:1/13:
 #0: ffff8880b863ae60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:652
 #1: ffff8880b8624588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
 #2: ffff88803666c0d8 (&type->s_umount_key#33){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:565
1 lock held by khungtaskd/31:
 #0: ffffffff8e95caa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8e95caa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #0: ffffffff8e95caa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:4/62:
 #0: ffff8880b873ae60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:652
 #1: ffff8880b8724588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933
1 lock held by klogd/5181:
 #0: ffff8880b863ae60 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x31/0x150 kernel/sched/core.c:652
2 locks held by getty/5579:
 #0: ffff88803754f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13a0 drivers/tty/n_tty.c:2211
4 locks held by udevd/5897:
 #0: ffff88806026d1b8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:183
 #1: ffff88805a2c8c80 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
 #2: ffff888053dd2878 (kn->active#27){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888053dd2878 (kn->active#27){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
 #3: ffff88807c9d41d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:954 [inline]
 #3: ffff88807c9d41d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
6 locks held by kworker/1:5/5913:
6 locks held by kworker/0:7/5960:
 #0: ffff888022af7540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff888022af7540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc90004f67c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc90004f67c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
 #2: ffff88802a78a1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #2: ffff88802a78a1d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899
 #3: ffff88807be8f1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #3: ffff88807be8f1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1056
 #4: ffff8880343601a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #4: ffff8880343601a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1056
 #5: ffffffff8fd3fc80 (register_mutex#6){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
 #5: ffffffff8fd3fc80 (register_mutex#6){+.+.}-{4:4}, at: usb_audio_probe+0x63a/0x2380 sound/usb/card.c:952
4 locks held by udevd/5969:
 #0: ffff888052022098 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:183
 #1: ffff88807b9a3880 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
 #2: ffff88805259bb48 (kn->active#27){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff88805259bb48 (kn->active#27){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
 #3: ffff88807be8f1d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:954 [inline]
 #3: ffff88807be8f1d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
4 locks held by udevd/6244:
 #0: ffff88802a46cab8 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xb7/0xe10 fs/seq_file.c:183
 #1: ffff888028a93080 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5c/0x420 fs/kernfs/file.c:172
 #2: ffff88802a635a58 (kn->active#27){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff88802a635a58 (kn->active#27){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:173
 #3: ffff88807d1bf1d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:954 [inline]
 #3: ffff88807d1bf1d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
3 locks held by kworker/0:11/7773:
 #0: ffff88813fe53140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff88813fe53140 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc90003277c40 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc90003277c40 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
 #2: ffffffff8e962da8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
 #2: ffffffff8e962da8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
6 locks held by kworker/1:12/7776:
 #0: ffff888022af7540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff888022af7540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc900033f7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc900033f7c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
 #2: ffff88802a8021d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #2: ffff88802a8021d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899
 #3: ffff88807c9d41d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #3: ffff88807c9d41d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1056
 #4: ffff8880297df1a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #4: ffff8880297df1a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1056
 #5: ffffffff8fd3fc80 (register_mutex#6){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
 #5: ffffffff8fd3fc80 (register_mutex#6){+.+.}-{4:4}, at: usb_audio_probe+0x63a/0x2380 sound/usb/card.c:952
6 locks held by kworker/0:13/7784:
 #0: ffff888022af7540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff888022af7540 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc90003427c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc90003427c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
 #2: ffff88802a7521d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #2: ffff88802a7521d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x17f/0x4f30 drivers/usb/core/hub.c:5899
 #3: ffff88802a3ce1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #3: ffff88802a3ce1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1056
 #4: ffff88807b6991a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:949 [inline]
 #4: ffff88807b6991a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1056
 #5: ffffffff8fd3fc80 (register_mutex#6){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
 #5: ffffffff8fd3fc80 (register_mutex#6){+.+.}-{4:4}, at: usb_audio_probe+0x63a/0x2380 sound/usb/card.c:952
4 locks held by syz.8.776/9010:
 #0: ffff888063f6cea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline]
 #0: ffff888063f6cea0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x212/0x5a0 net/bluetooth/hci_core.c:2716
 #1: ffff888063f6c0b8 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x640/0x10e0 net/bluetooth/hci_sync.c:5356
 #2: ffffffff8ff66ae0 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline]
 #2: ffffffff8ff66ae0 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xa1/0x260 net/bluetooth/hci_conn.c:2650
 #3: ffff88807eae32f8 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x92/0x570 net/bluetooth/l2cap_core.c:1777
1 lock held by syz.9.780/9030:
 #0: ffffffff8e962da8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
 #0: ffffffff8e962da8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x38d/0x770 kernel/rcu/tree_exp.h:961
1 lock held by rm/9054:

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 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+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xfaa/0x1000 kernel/hung_task.c:515
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:check_preemption_disabled+0x21/0xe0 lib/smp_processor_id.c:53
Code: 90 90 90 90 90 90 90 90 90 55 41 57 41 56 53 65 8b 05 a7 ef 8b 07 65 8b 0d 9c ef 8b 07 f7 c1 ff ff ff 7f 74 0c 5b 41 5e 41 5f <5d> c3 cc cc cc cc cc 9c 59 f7 c1 00 02 00 00 74 ea 65 4c 8b 3d 4e
RSP: 0018:ffffc90000147ad0 EFLAGS: 00000006
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000080000100
RDX: 0000000000000000 RSI: ffffffff8dfde352 RDI: ffffffff8c282a00
RBP: ffffffff81abcc51 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff2065937 R12: 0000000000000002
R13: ffffffff8e95cbc0 R14: 0000000000000000 R15: 0000000000000246
FS:  0000000000000000(0000) GS:ffff88812523d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005644d012f008 CR3: 000000007f6e6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline]
 lock_acquire+0xcd/0x350 kernel/locking/lockdep.c:5867
 rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 rcu_do_batch kernel/rcu/tree.c:2611 [inline]
 rcu_core+0x76e/0x1070 kernel/rcu/tree.c:2869
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>