Re: mfd: lpc_ich: NULL pointer dereference at (second) module removal

[Samuel Ortiz]

Hi Paul, Peter,

On Mon, Nov 12, 2012 at 11:31:15AM -0600, Peter Tyser wrote:
> Thanks for reporting the issue!
> 
> On Fri, 2012-11-09 at 14:19 +0100, Paul Bolle wrote:
> > 0) I can trigger a NULL pointer dereference if I remove the lpc_ich
> > module. This seems to only happen if I remove it for the second time
> > (ie, remove the module, insert it and remove it again). This happens
> > both on i686 and x86_64 (different setups, as inserting the module
> > triggers different messages about the initialization of the MFD cells on
> > these machines). Both machines are running v3.6.6.
> 
> I believe this is caused by the fact that non-MFD devices get attached
> to the same parent as the iTCO_wdt driver, which is an MFD.  When the
> MFD code attempts unregister the MFD drivers, it oops when the non-MFD
> devices are accessed since they don't have the mfd_cell node.
That's probably correct. I just merged commit
5dc4dda91c86ef82bd53d77e5de50ec095b33e46 into my for-next branch and that one
could fix that issue. Could you guys please give it a go ? This is the actual
patch: