Re: [PATCH v2 1/2] mm, kasan: improve double-free detection

[Yury Norov]

On Sat, May 07, 2016 at 03:15:59PM +0000, Luruo, Kuthonuzo wrote:
> Thank you for the review!
> 
> > > +	switch (alloc_data.state) {
> > > +	case KASAN_STATE_QUARANTINE:
> > > +	case KASAN_STATE_FREE:
> > > +		kasan_report((unsigned long)object, 0, false,
> > > +				(unsigned long)__builtin_return_address(1));
> > 
> > __builtin_return_address() is unsafe if argument is non-zero. Use
> > return_address() instead.
> 
> hmm, I/cscope can't seem to find an x86 implementation for return_address().
> Will dig further; thanks.
> 

It seems there's no generic interface to obtain return address. x86
has  working __builtin_return_address() and it's ok with it, others
use their own return_adderss(), and ok as well.

I think unification is needed here.