Re: [PATCH v11 25/25] x86/cet/shstk: Add arch_prctl functions for shadow stack

Dave Hansen
2020-09-10T02:25:58Z

On 9/9/20 4:07 PM, Yu, Yu-cheng wrote:
> What if a writable mapping is passed to madvise(MADV_SHSTK)?  Should
> that be rejected?

It doesn't matter to me. Even if it's readable, it _stops_ being even
directly readable after it's a shadow stack, right? I don't think
writes are special in any way. If anything, we *want* it to be writable
because that indicates that it can be written to, and we will want to
write to it soon.