Re: [PATCH] arm64: increase stack size for KASAN_EXTRA

Qian Cai
2018-12-12T03:54:42Z

On 12/11/18 6:06 PM, Arnd Bergmann wrote:
>> I am thinking about something it is probably best just waiting for those major
>> distors to complete upgrading to GCC9 or back-porting those stack reduction
>> patches first. Then, it is good time to tie up loose ends for those default
>> stack sizes in all combinations.
>
> I was basically trying to make sure we don't forget it when it gets to that.

I added a reminder in my calendar to check the GCC9 adoption in Q2 FY19.

>
> Another alternative would be to just disable KASAN_EXTRA now
> for gcc versions before 9, which essentially means for everyone,
> but then we get it back once a working version gets released. As
> I understand, this kasan option is actually fairly useless given its
> cost, so very few people would miss it.
>
> On a related note, I think we have to turn off asan-stack entirely
> on all released clang versions. asan-stack in general is much more
> useful than the use-after-scope check, but we clang produces some
> very large stack frames with it and we probably can't even work
> around it with KASAN_THREAD_SHIFT=2 but would need even
> more than that otherwise.
>
> Arnd
>