Re: tty_register_device NULL pointer dereference in 2.6.31-rc4

Dave Young
2009-07-27T14:07:36Z

On Mon, Jul 27, 2009 at 01:39:03PM +0200, Oliver Hartkopp wrote:
> Oliver Hartkopp wrote:
> > Dave Young wrote:
> >> On Sat, Jul 25, 2009 at 01:10:46PM +0100, Alan Cox wrote:
> >>>>> tty_register_device appears to have been called with a NULL pointer. Not
> >>>>> sure why however.
> >>>> if that is the pointer for the struct device, then that used to be fine
> >>>> in the past. Not all RFCOMM device have a parent when they are created.
> >>> The tty layer doesn't care about the struct device really. Nothing there
> >>> has changed. The NULL passed appears to be the driver argument.
> >> Agree with you, because in rfcomm_init, rfcomm thread run before tty initilized, the following patch may fix the problem.
> >> oliver, could you verify it it fix your problem?
> >
> > Hi Dave,
> >
> > i get this problem really seldom on my Laptop and i did not manage to get a
> > reproducible Oops of that problem.
> >
> > Anyway the code you are pointing to seems to have a problem and your added
> > error handling looks good to me - even if i don't know if the initializations
> > can be reordered in that way.
> >
> > I'll try your patch, but it could take a *long* time to prove it right ;-)
> >
>
> Just FYI:
>
> Your patch compiled, the system booted without problems and nothing is broken
> so far. I checked the BT, WLAN and BT dial-up with success. So it looks good
> to me.

Thanks for the testing. Marcel, could you take a look?

>
> Regards,
> Oliver