Re: INFO: task hung in hub_port_init

[Andrey Konovalov]

On Tue, Oct 6, 2020 at 10:56 AM Oliver Neukum <oneukum@xxxxxxx> wrote:
>
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=152bb760500000
> > final oops:     https://syzkaller.appspot.com/x/report.txt?x=172bb760500000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=132bb760500000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+74d6ef051d3d2eacf428@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Fixes: 6dcf45e51497 ("sh_eth: use correct name for ECMR_MPDE bit")
> >
> > INFO: task kworker/0:0:5 blocked for more than 143 seconds.
> >       Not tainted 5.9.0-rc7-syzkaller #0
> > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> > task:kworker/0:0     state:D stack:27664 pid:    5 ppid:     2 flags:0x00004000
> > Workqueue: usb_hub_wq hub_event
> > Call Trace:
> >  context_switch kernel/sched/core.c:3778 [inline]
> >  __schedule+0xec9/0x2280 kernel/sched/core.c:4527
> >  schedule+0xd0/0x2a0 kernel/sched/core.c:4602
>
> By this time urb_dequeue() has been killed and has returned.
>
> >  usb_kill_urb.part.0+0x197/0x220 drivers/usb/core/urb.c:696
> >  usb_kill_urb+0x7c/0x90 drivers/usb/core/urb.c:691
> >  usb_start_wait_urb+0x24a/0x2b0 drivers/usb/core/message.c:64
> >  usb_internal_control_msg drivers/usb/core/message.c:102 [inline]
> >  usb_control_msg+0x31c/0x4a0 drivers/usb/core/message.c:153
> >  hub_port_init+0x11ae/0x2d80 drivers/usb/core/hub.c:4689
> >  hub_port_connect drivers/usb/core/hub.c:5140 [inline]
> >  hub_port_connect_change drivers/usb/core/hub.c:5348 [inline]
> >  port_event drivers/usb/core/hub.c:5494 [inline]
> >
>
> This looks like it should.
>
> Which HC driver are you using for these tests?

Hi Oliver,

This is the USB/IP one, based on what I see in the reproducer.

Thanks!

> It looks like
> the HCD is not acting on urb_dequeue(), rather than a locking
> issue.