INFO: task kworker/1:20:12124 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:20    state:D stack:22920 pid:12124 ppid:2      flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6833
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x6a9/0xcc0 kernel/locking/mutex.c:747
 usb_audio_probe+0x3b3/0x1df0 sound/usb/card.c:813
 usb_probe_interface+0x5c9/0xb20 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x25b/0xb20 drivers/base/dd.c:658
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:800
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:830
 __device_attach_driver+0x2ca/0x510 drivers/base/dd.c:958
 bus_for_each_drv+0x252/0x2e0 drivers/base/bus.c:459
 __device_attach+0x2c2/0x420 drivers/base/dd.c:1030
 bus_probe_device+0x180/0x260 drivers/base/bus.c:534
 device_add+0x85b/0xc20 drivers/base/core.c:3683
 usb_set_configuration+0x1a79/0x20c0 drivers/usb/core/message.c:2265
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x13d/0x270 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x25b/0xb20 drivers/base/dd.c:658
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:800
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:830
 __device_attach_driver+0x2ca/0x510 drivers/base/dd.c:958
 bus_for_each_drv+0x252/0x2e0 drivers/base/bus.c:459
 __device_attach+0x2c2/0x420 drivers/base/dd.c:1030
 bus_probe_device+0x180/0x260 drivers/base/bus.c:534
 device_add+0x85b/0xc20 drivers/base/core.c:3683
 usb_new_device+0xa3c/0x1660 drivers/usb/core/hub.c:2660
 hub_port_connect drivers/usb/core/hub.c:5529 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5669 [inline]
 port_event drivers/usb/core/hub.c:5833 [inline]
 hub_event+0x29bf/0x49f0 drivers/usb/core/hub.c:5915
 process_one_work kernel/workqueue.c:2653 [inline]
 process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Showing all locks held in the system:
6 locks held by kworker/0:1/9:
 #0: ffff888145a4e138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
 #0: ffff888145a4e138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730
 #1: ffffc900000e7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
 #1: ffffc900000e7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730
 #2: ffff8881433c7190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #2: ffff8881433c7190 (&dev->mutex){....}-{3:3}, at: hub_event+0x180/0x49f0 drivers/usb/core/hub.c:5861
 #3: ffff888058d86190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #3: ffff888058d86190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x420 drivers/base/dd.c:1005
 #4: ffff88805949a160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #4: ffff88805949a160 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x420 drivers/base/dd.c:1005
 #5: ffffffff8e364c68 (register_mutex#6){+.+.}-{3:3}, at: usb_audio_probe+0x3b3/0x1df0 sound/usb/card.c:813
1 lock held by khungtaskd/29:
 #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #0: ffffffff8d1320e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x290 kernel/locking/lockdep.c:6633
3 locks held by kworker/u4:2/34:
2 locks held by kworker/u4:11/1331:
 #0: ffff8880b8f3c018 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
 #1: ffff8880b8f289c0 (psi_seq){-.-.}-{0:0}, at: psi_sched_switch kernel/sched/stats.h:189 [inline]
 #1: ffff8880b8f289c0 (psi_seq){-.-.}-{0:0}, at: __schedule+0x2176/0x45a0 kernel/sched/core.c:6695
1 lock held by dhcpcd/5434:
2 locks held by getty/5532:
 #0: ffff88814c88b0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000328b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x433/0x1390 drivers/tty/n_tty.c:2217
6 locks held by kworker/0:7/8927:
6 locks held by kworker/1:20/12124:
 #0: ffff888145a4e138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
 #0: ffff888145a4e138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730
 #1: ffffc9000450fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
 #1: ffffc9000450fd00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730
 #2: ffff8880254ef190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #2: ffff8880254ef190 (&dev->mutex){....}-{3:3}, at: hub_event+0x180/0x49f0 drivers/usb/core/hub.c:5861
 #3: ffff888058d34190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #3: ffff888058d34190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x420 drivers/base/dd.c:1005
 #4: ffff88803057c160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline]
 #4: ffff88803057c160 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x420 drivers/base/dd.c:1005
 #5: ffffffff8e364c68 (register_mutex#6){+.+.}-{3:3}, at: usb_audio_probe+0x3b3/0x1df0 sound/usb/card.c:813
4 locks held by udevd/18110:
 #0: ffff888065a51b08 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb1/0xd50 fs/seq_file.c:182
 #1: ffff8880698e4888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x5c/0x410 fs/kernfs/file.c:172
 #2: ffff88802d9ccd98 (kn->active#18){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff88802d9ccd98 (kn->active#18){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x410 fs/kernfs/file.c:173
 #3: ffff888058d34190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:1000 [inline]
 #3: ffff888058d34190 (&dev->mutex){....}-{3:3}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142
2 locks held by kworker/1:2/19427:
 #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
 #0: ffff888017c72538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730
 #1: ffffc900033dfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline]
 #1: ffffc900033dfd00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730
3 locks held by kworker/u4:3/26178:
2 locks held by syz-executor/26838:
 #0: ffff8880255940e0 (&type->s_umount_key#107){+.+.}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880255940e0 (&type->s_umount_key#107){+.+.}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff8880255940e0 (&type->s_umount_key#107){+.+.}-{3:3}, at: deactivate_super+0xa4/0xe0 fs/super.c:513
 #1: ffffffff8d137ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
 #1: ffffffff8d137ab8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x306/0x880 kernel/rcu/tree_exp.h:1004

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a6/0x3e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf3d/0xf80 kernel/hung_task.c:379
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5434 Comm: dhcpcd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:-1 [inline]
RIP: 0010:unwind_next_frame+0x1ccf/0x2970 arch/x86/kernel/unwind_orc.c:665
Code: c7 04 a4 00 49 8b 07 4c 39 f3 0f 96 c1 4c 39 f0 0f 97 c2 84 d1 74 3c 49 8d 4e 08 48 39 d9 0f 96 c2 48 39 c1 0f 97 c0 49 39 ee <0f> 97 c3 08 c3 08 d3 4c 89 f7 48 89 ee e8 6f cf 4b 00 80 fb 01 0f
RSP: 0018:ffffc900032f74b0 EFLAGS: 00000202
RAX: ffffc900032f8000 RBX: ffffc900032f0000 RCX: ffffc900032f75f0
RDX: ffff88802b659e00 RSI: 0000000000000001 RDI: ffffc900032f75f0
RBP: ffffc900032f7580 R08: ffff88802b659e00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffc900032f75e8
R13: dffffc0000000000 R14: ffffc900032f75e8 R15: ffffc900032f75f8
FS:  00007f1cae86d740(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f035f7ea540 CR3: 000000002c541000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 __unwind_start+0x66a/0x7e0 arch/x86/kernel/unwind_orc.c:760
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x270 mm/slub.c:3852
 __unix_dgram_recvmsg+0x9fa/0xd80 net/unix/af_unix.c:2490
 sock_recvmsg_nosec net/socket.c:1046 [inline]
 sock_recvmsg net/socket.c:1068 [inline]
 sock_read_iter+0x2d9/0x3e0 net/socket.c:1138
 call_read_iter include/linux/fs.h:2012 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x46a/0x970 fs/read_write.c:470
 ksys_read+0x150/0x260 fs/read_write.c:613
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1cae8f7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffeb394e9c0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f1cae86d740 RCX: 00007f1cae8f7407
RDX: 0000000000000408 RSI: 00007ffeb394ea10 RDI: 0000000000000007
RBP: 00007ffeb394f120 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055f7b5d875e0
R13: 000055f7f3064d90 R14: 0000000000000000 R15: 00007ffeb394eed0
 </TASK>