INFO: task kworker/1:5:5892 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:21448 pid:5892 ppid:2 flags:0x00004000 Workqueue: usb_hub_wq hub_event Call Trace: 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 Showing all locks held in the system: 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 2 locks held by getty/5529: #0: ffff88814cf4c0a0 (&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 2 locks held by kworker/u5:3/5779: #0: ffff888021a8a138 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888021a8a138 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc9000485fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc9000485fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 2 locks held by kworker/u5:6/5784: #0: ffff888021a8a138 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888021a8a138 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc9000494fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc9000494fd00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 6 locks held by kworker/1:5/5892: #0: ffff888148279538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888148279538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc90005577d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc90005577d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #2: ffff888143767190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #2: ffff888143767190 (&dev->mutex){....}-{3:3}, at: hub_event+0x180/0x49f0 drivers/usb/core/hub.c:5861 #3: ffff888062110190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #3: ffff888062110190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x420 drivers/base/dd.c:1005 #4: ffff88807623f160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #4: ffff88807623f160 (&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 2 locks held by kworker/u4:14/10957: #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 2 locks held by kworker/u5:0/12462: #0: ffff888021a8a138 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888021a8a138 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc900036d7d00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc900036d7d00 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 6 locks held by kworker/1:7/13892: 6 locks held by kworker/0:11/14400: #0: ffff888148279538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888148279538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc900032f7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc900032f7d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #2: ffff8880251d7190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #2: ffff8880251d7190 (&dev->mutex){....}-{3:3}, at: hub_event+0x180/0x49f0 drivers/usb/core/hub.c:5861 #3: ffff88803107c190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #3: ffff88803107c190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x420 drivers/base/dd.c:1005 #4: ffff88801d7b3160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #4: ffff88801d7b3160 (&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 6 locks held by kworker/0:13/14402: #0: ffff888148279538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #0: ffff888148279538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #1: ffffc90003327d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2628 [inline] #1: ffffc90003327d00 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x96f/0x15d0 kernel/workqueue.c:2730 #2: ffff888143731190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #2: ffff888143731190 (&dev->mutex){....}-{3:3}, at: hub_event+0x180/0x49f0 drivers/usb/core/hub.c:5861 #3: ffff88807ea17190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #3: ffff88807ea17190 (&dev->mutex){....}-{3:3}, at: __device_attach+0x89/0x420 drivers/base/dd.c:1005 #4: ffff88802fc1f160 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:995 [inline] #4: ffff88802fc1f160 (&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/15009: #0: ffff88802ce9f9e0 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb1/0xd50 fs/seq_file.c:182 #1: ffff888077f25888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x5c/0x410 fs/kernfs/file.c:172 #2: ffff88802beb49b8 (kn->active#18){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802beb49b8 (kn->active#18){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x410 fs/kernfs/file.c:173 #3: ffff888062110190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:1000 [inline] #3: ffff888062110190 (&dev->mutex){....}-{3:3}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/15013: #0: ffff88802de25540 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb1/0xd50 fs/seq_file.c:182 #1: ffff8880250dcc88 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x5c/0x410 fs/kernfs/file.c:172 #2: ffff88814d3475d8 (kn->active#18){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88814d3475d8 (kn->active#18){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x410 fs/kernfs/file.c:173 #3: ffff88807a154190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:1000 [inline] #3: ffff88807a154190 (&dev->mutex){....}-{3:3}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/16833: #0: ffff888025dbf540 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xb1/0xd50 fs/seq_file.c:182 #1: ffff88805ba26088 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x5c/0x410 fs/kernfs/file.c:172 #2: ffff8880543318c0 (kn->active#18){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8880543318c0 (kn->active#18){++++}-{0:0}, at: kernfs_seq_start+0xb2/0x410 fs/kernfs/file.c:173 #3: ffff88807ea17190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:1000 [inline] #3: ffff88807ea17190 (&dev->mutex){....}-{3:3}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: 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 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5126 Comm: klogd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:80 [inline] RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:699 Code: 84 1d ff ff ff eb 8a e8 ce 83 15 09 48 c7 c7 40 89 13 8d 4c 89 f6 e8 6f 67 ec 02 e9 44 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1e fa 41 57 41 56 53 65 ff 05 88 cf 92 7e e8 8b 99 15 09 89 RSP: 0018:ffffc900032d7ae0 EFLAGS: 00000202 RAX: ffffffff8872adfe RBX: ffff88807fa24000 RCX: 0000000000000000 RDX: ffff88807e448000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff2238ca0 R10: dffffc0000000000 R11: fffffbfff2238ca1 R12: ffffc900032d7c20 R13: dffffc0000000000 R14: ffffffff8872adcd R15: 0000000000000001 FS: 00007fc345fe5c80(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f16ac1e8158 CR3: 000000007e966000 CR4: 00000000003506e0 Call Trace: rcu_read_lock include/linux/rcupdate.h:787 [inline] sock_def_readable+0xe7/0x420 net/core/sock.c:3351 unix_dgram_sendmsg+0x106e/0x16d0 net/unix/af_unix.c:2141 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x4a9/0x6b0 net/socket.c:2200 __do_sys_sendto net/socket.c:2212 [inline] __se_sys_sendto net/socket.c:2208 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2208 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: 0033:0x7fc346135407 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:00007ffec4628ed0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007fc345fe5c80 RCX: 00007fc346135407 RDX: 0000000000000049 RSI: 00007ffec4629010 RDI: 0000000000000003 RBP: 00007ffec4629440 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffec4629458 R13: 00007ffec4629010 R14: 000000000000002e R15: 00007ffec4629010