INFO: task kworker/1:2:780 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:2 state:D stack:20472 pid:780 tgid:780 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:726 [inline] __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820 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 INFO: task kworker/0:7:5491 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:7 state:D stack:21144 pid:5491 tgid:5491 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:726 [inline] __mutex_lock+0xced/0x1b10 kernel/locking/mutex.c:820 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: 1 lock held by khungtaskd/30: #0: ffffffff896de8e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff896de8e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline] #0: ffffffff896de8e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 6 locks held by kworker/1:2/780: #0: ffff888105ea4140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc900030bfd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810c7511d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88810c7511d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff8881243031d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff8881243031d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff88811f1001a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88811f1001a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa1b8a0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa1b8a0 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 6 locks held by kworker/0:2/1128: 2 locks held by getty/2922: #0: ffff8881167330a0 (&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/5217: #0: ffff8881362c4758 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88812021d880 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff8881247ec3c8 (kn->active#24){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8881247ec3c8 (kn->active#24){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88811ce421d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff88811ce421d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 4 locks held by udevd/5276: #0: ffff88811acbc878 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88811f793c80 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff88813dcf34b8 (kn->active#24){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88813dcf34b8 (kn->active#24){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff88813a2be1d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff88813a2be1d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 6 locks held by kworker/0:7/5491: #0: ffff888105ea4140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc90004477d18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810c7691d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88810c7691d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff8881202a51d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff8881202a51d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff8881191b91a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff8881191b91a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa1b8a0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa1b8a0 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 4 locks held by udevd/7759: #0: ffff88811ef2a518 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x1270 fs/seq_file.c:183 #1: ffff88811b521080 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x4f/0x2a0 fs/kernfs/file.c:172 #2: ffff88813653b3c8 (kn->active#24){++++}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88813653b3c8 (kn->active#24){++++}-{0:0}, at: kernfs_seq_start+0xbc/0x2a0 fs/kernfs/file.c:173 #3: ffff8881202a51d8 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1045 [inline] #3: ffff8881202a51d8 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 2 locks held by kworker/0:3/8074: #0: ffff88810006b140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc90013b4fd18 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 6 locks held by kworker/0:0/14719: #0: ffff888105ea4140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc90004377d18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810c3e11d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88810c3e11d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88813a2be1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff88813a2be1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #4: ffff88813d4141a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88813d4141a0 (&dev->mutex){....}-{4:4}, at: __device_attach+0x7e/0x4d0 drivers/base/dd.c:1076 #5: ffffffff8aa1b8a0 (register_mutex#3){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline] #5: ffffffff8aa1b8a0 (register_mutex#3){+.+.}-{4:4}, at: usb_audio_probe+0x385/0x3b60 sound/usb/card.c:952 5 locks held by kworker/1:8/15425: #0: ffff888105ea4140 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12d6/0x1980 kernel/workqueue.c:3277 #1: ffffc9001543fd18 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x973/0x1980 kernel/workqueue.c:3278 #2: ffff88810cb011d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #2: ffff88810cb011d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff8881241261d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #3: ffff8881241261d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0x10a/0x9a0 drivers/usb/core/hub.c:2336 #4: ffff88811be3e1a0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1040 [inline] #4: ffff88811be3e1a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1174 [inline] #4: ffff88811be3e1a0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1372 2 locks held by syz.1.3548/19876: 3 locks held by sed/19891: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 2860 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:iterate_chain_key kernel/locking/lockdep.c:453 [inline] RIP: 0010:__lock_acquire+0x580/0x2630 kernel/locking/lockdep.c:5225 Code: f7 c1 c2 10 41 89 f8 31 c2 89 d0 29 d6 01 fa c1 c8 0d 31 c6 89 f0 41 29 f0 01 f2 c1 c0 04 89 d2 44 31 c0 48 c1 e0 20 48 09 d0 <49> 89 c7 4d 85 e4 74 46 8b 85 40 0b 00 00 4c 8d b5 48 0b 00 00 45 RSP: 0018:ffffc9000146f838 EFLAGS: 00000006 RAX: 0ac0d5affe09d4ff RBX: ffff888117330b48 RCX: 0000000000000000 RDX: 00000000fe09d4ff RSI: 0000000068c1bacb RDI: 00000000ef9d33e4 RBP: ffff888117330000 R08: 0000000086db7919 R09: 0000000000000007 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000007 R14: 0000000000020000 R15: 0000000000000005 FS: 00007fece7bfa880(0000) GS:ffff8882686a8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f58d9d52480 CR3: 0000000117f10000 CR4: 00000000003506f0 Call Trace: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xd1/0x2090 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 security_file_free+0x65/0xa0 security/security.c:2442 file_free fs/file_table.c:97 [inline] __fput+0x553/0xb50 fs/file_table.c:523 fput_close_sync+0x118/0x250 fs/file_table.c:615 __do_sys_close fs/open.c:1507 [inline] __se_sys_close fs/open.c:1492 [inline] __x64_sys_close+0x8b/0x120 fs/open.c:1492 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0x7f0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fece7d56a67 Code: 44 00 00 48 83 ec 10 48 63 ff 45 31 c9 45 31 c0 6a 01 31 c9 e8 ca 19 f9 ff 48 83 c4 18 c3 0f 1f 44 00 00 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 61 b3 0d 00 f7 d8 64 89 02 b8 RSP: 002b:00007ffd91705778 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 000055f44de81ff0 RCX: 00007fece7d56a67 RDX: 00000000000272d1 RSI: 00007fece7e32b20 RDI: 000000000000000d RBP: 000055f44de3c070 R08: 000000000001f290 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000202 R12: 000055f44de409c0 R13: 00000000000000ff R14: 000055f439d18be0 R15: 00007ffd917059f0