Re: WARNING in usbhid_raw_request/usb_submit_urb (2)

[Andrey Konovalov]

On Thu, Jan 9, 2020 at 5:46 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, 8 Jan 2020, syzbot wrote:
>
> > Hello,
> >
> > syzbot has tested the proposed patch and the reproducer did not trigger
> > crash:
> >
> > Reported-and-tested-by:
> > syzbot+10e5f68920f13587ab12@xxxxxxxxxxxxxxxxxxxxxxxxx
> >
> > Tested on:
> >
> > commit:         ecdf2214 usb: gadget: add raw-gadget interface
> > git tree:       https://github.com/google/kasan.git
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=b06a019075333661
> > dashboard link: https://syzkaller.appspot.com/bug?extid=10e5f68920f13587ab12
> > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > patch:          https://syzkaller.appspot.com/x/patch.diff?x=1583963ee00000
> >
> > Note: testing is done by a robot and is best-effort only.
>
> I'm at a loss for a way to track this down any farther.  The difference
> between this patch and the previous was very small and almost entirely
> confined to actions that take place _after_ the bug condition has been
> detected.
>
> If this is indeed caused by a race, it would be nice to know that the
> two racing threads are doing.  One of them we can see in the log output
> (it's calling usb_control_msg) but the other is a mystery.

I've tried to reproduce this manually, but failed :( I don't think
there's anything else we can do with this. Let's close this bug,
there's a chance syzbot comes up with a better reproducer.

#syz invalid