Re: [syzbot] [usb?] INFO: task hung in usb_register_dev (2)

[Oliver Neukum <oneukum@suse.com>]

On 07.10.24 13:05, syzbot wrote:

> INFO: task kworker/1:0:25 blocked for more than 144 seconds.
>        Not tainted 6.12.0-rc1-next-20241003-syzkaller #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:kworker/1:0     state:D stack:20416 pid:25    tgid:25    ppid:2      flags:0x00004000
> Workqueue: pm pm_runtime_work
> Call Trace:
>   <TASK>
>   context_switch kernel/sched/core.c:5315 [inline]
>   __schedule+0x1895/0x4b30 kernel/sched/core.c:6675
>   __schedule_loop kernel/sched/core.c:6752 [inline]
>   schedule+0x14b/0x320 kernel/sched/core.c:6767
>   usb_poison_urb+0x1bc/0x2e0 drivers/usb/core/urb.c:763

This points to a bug in the HCD.
usb_poison_urb() is guaranteed to make progress.

>   poison_urbs drivers/usb/class/cdc-wdm.c:342 [inline]
>   wdm_suspend+0x174/0x380 drivers/usb/class/cdc-wdm.c:1271
>   usb_suspend_interface drivers/usb/core/driver.c:1328 [inline]
>   usb_suspend_both+0x2a5/0x1140 drivers/usb/core/driver.c:1433
>   usb_runtime_suspend+0x59/0x100 drivers/usb/core/driver.c:1968

What HC is used for these tests?

	Regards
		Oliver