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

[Dmitry Vyukov]

On Sun, May 8, 2016 at 11:17 AM, Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx> wrote:
> 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.


We use _RET_IP_ in other places in portable part of kasan.