alignment faults in 3.6

[Russell King - ARM Linux]

On Fri, Oct 05, 2012 at 07:24:44AM -0500, Rob Herring wrote:
> On 10/05/2012 03:24 AM, Russell King - ARM Linux wrote:
> > Does it matter?  I'm just relaying the argument against adding __packed
> > which was used before we were forced (by the networking folk) to implement
> > the alignment fault handler.
> 
> It doesn't really matter what will be accepted or not as adding __packed
> to struct iphdr doesn't fix the problem anyway. gcc still emits a ldm.
> The only way I've found to eliminate the alignment fault is adding a
> barrier between the 2 loads. That seems like a compiler issue to me if
> there is not a better fix.

Even so, please test the patch I've sent you in the sub-thread - that
needs testing whether or not GCC is at fault.  Will's patch to add the
warnings _has_ uncovered a potential issue with the use of __get_user()
in some parts of the ARM specific kernel, and I really need you to test
that while you're experiencing this problem.