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

Dave Hansen
2020-09-14T21:14:41Z

On 9/14/20 11:31 AM, Andy Lutomirski wrote:
> No matter what we do, the effects of calling vfork() are going to be a
> bit odd with SHSTK enabled. I suppose we could disallow this, but
> that seems likely to cause its own issues.

What's odd about it? If you're a vfork()'d child, you can't touch the
stack at all, right? If you do, you or your parent will probably die a
horrible death.

The extra shadow stacks sanity checks means we'll probably see shadow
stack exceptions instead of the slightly more chaotic death without them.