Re: [PATCH][next] wifi: rtl8xxxu: Avoid -Wflex-array-member-not-at-end warnings

[Michal Pecio <michal.pecio@gmail.com>]

Hi,

> >> I got something. In my case everything seemed fine until I
> >> unplugged the wifi adapter. And then the system still worked for a
> >> few minutes before it froze.

Sounds like memory corruption.

> > Zenm and I tested below changes which can also reproduce the
> > symptom, so I wonder driver might assume urb is the first member of
> > struct, but unfortunately I can't find that.

That's what it seems to be doing, because it uses usb_init_urb()
on urbs embedded in some struct and then usb_free_urb().

If you look what usb_free_urb() does, it decrements refcount and
attempts to free urb. But here urb is a member of a larger struct,
so I guess the whole struct is freed (and this was either intentional
or a bug that didn't happen to blow up yet).

Now a bogus address is being passed to kfree() and things go boom.
Or at least that's my first guess after spending a few minutes.
But that's the direction I would be looking at.

Regards,
Michal