syzbot


INFO: task hung in devtmpfs_delete_node (3)

Status: auto-obsoleted due to no activity on 2026/06/21 03:37
Subsystems: kernel
Labels: prio:high
[Documentation on labels]
First crash: 91d, last: 91d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
fc3ca26f-3764-478e-94b1-0e21881944bb assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ✅ VMHostTrigger: ❌ INFO: task hung in devtmpfs_delete_node (3) 2026/05/24 14:57 2026/05/24 14:57 2026/05/24 15:40 c69befb30ac10e158cc9d1557b508ee3f0eca1de

			
		
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in devtmpfs_delete_node kernel 1 1 568d 568d 0/29 auto-obsoleted due to no activity on 2025/02/28 23:11
linux-5.15 INFO: task hung in devtmpfs_delete_node 1 1 785d 785d 0/3 auto-obsoleted due to no activity on 2024/08/06 06:15
android-6-12 INFO: task hung in devtmpfs_delete_node 1 1 143d 143d 0/1 auto-obsoleted due to no activity on 2026/04/30 13:35
upstream INFO: task hung in devtmpfs_delete_node (2) kernel 1 6 427d 428d 0/29 auto-obsoleted due to no activity on 2025/07/20 08:17

Sample crash report:
INFO: task kworker/1:2:883 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:23672 pid:883   tgid:883   ppid:2      task_flags:0x4288060 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xeb1/0x4220 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7008
 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
 devtmpfs_submit_req drivers/base/devtmpfs.c:121 [inline]
 devtmpfs_delete_node+0x156/0x1d0 drivers/base/devtmpfs.c:170
 device_del+0x717/0x9b0 drivers/base/core.c:3857
 usb_disconnect+0x5b5/0x9a0 drivers/usb/core/hub.c:2376
 hub_port_connect drivers/usb/core/hub.c:5407 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x1d0c/0x4af0 drivers/usb/core/hub.c:5953
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: task syz.4.41:5344 blocked for more than 171 seconds.
      Not tainted syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.41        state:D
 stack:27024 pid:5344  tgid:5343  ppid:2972   task_flags:0x40044c flags:0x00080003
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xeb1/0x4220 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7008
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
 kobject_uevent_env+0xba8/0x18b0 lib/kobject_uevent.c:608
 device_remove+0xcb/0x180 drivers/base/dd.c:571
 __device_release_driver drivers/base/dd.c:1284 [inline]
 device_release_driver_internal+0x42e/0x600 drivers/base/dd.c:1307
 driver_detach+0xd8/0x1b0 drivers/base/dd.c:1370
 bus_remove_driver+0x13b/0x2e0 drivers/base/bus.c:784
 driver_unregister+0x76/0xb0 drivers/base/driver.c:277
 usb_gadget_unregister_driver+0x49/0x70 drivers/usb/gadget/udc/core.c:1751
 raw_release+0x19b/0x260 drivers/usb/gadget/legacy/raw_gadget.c:463
 __fput+0x3ff/0xb40 fs/file_table.c:469
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8b8/0x2b60 kernel/exit.c:976
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x7e/0x430 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x671/0x7b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5b7573c42b
RSP: 002b:00007f5b7418cf00 EFLAGS: 00000246
 ORIG_RAX: 0000000000000010
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 00007f5b7573c42b
RDX: 00007f5b7418dfd0 RSI: 0000000080085502 RDI: 0000000000000003
RBP: 00007f5b7418dfd0 R08: 0000000000000024 R09: 00007f5b7418cfc8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000080085502
R13: 0000000800000000 R14: 0000000000000024 R15: 00007f5b757f0ee6
 </TASK>
INFO: task syz.2.43:5351 blocked for more than 172 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.43        state:D
 stack:28488 pid:5351  tgid:5350  ppid:2969   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xeb1/0x4220 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7008
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
 uevent_net_broadcast_untagged lib/kobject_uevent.c:317 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
 kobject_uevent_env+0xba8/0x18b0 lib/kobject_uevent.c:608
 gadget_bind_driver+0x773/0xbf0 drivers/usb/gadget/udc/core.c:1647
 call_driver_probe drivers/base/dd.c:583 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:661
 __driver_probe_device+0x1de/0x400 drivers/base/dd.c:803
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833
 __driver_attach+0x217/0x5c0 drivers/base/dd.c:1227
 bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:383
 bus_add_driver+0x305/0x5b0 drivers/base/bus.c:715
 driver_register+0x1e2/0x360 drivers/base/driver.c:249
 usb_gadget_register_driver_owner+0x132/0x210 drivers/usb/gadget/udc/core.c:1719
 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:596 [inline]
 raw_ioctl+0x1a85/0x2b80 drivers/usb/gadget/legacy/raw_gadget.c:1307
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0x7b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc1c77dc42b
RSP: 002b:00007fc1c622cf00 EFLAGS: 00000246
 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fc1c77dc42b
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000003
RBP: 00007fc1c622dfd0 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000200000000040 R14: 0000000000000005 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/0:0/9:
1 lock held by khungtaskd/30:
 #0: 
ffffffff896de6e0
 (
rcu_read_lock
){....}-{1:3}
, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:6/321:
 #0: 
ffff888112512148

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/23 03:34 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 84db3719d273 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in devtmpfs_delete_node
* Struck through repros no longer work on HEAD.