Re: [PATCH 2/2] x86_64,signal: Remove 'fs' and 'gs' from sigcontext

From: Andi Kleen
Date: Sat Jul 12 2014 - 14:38:04 EST


> This seems like it's asking for trouble. I think wxe'd have to
> separately save the selectors and the base registers to avoid breaking
> something, especially once wrgsbase, etc are enabled.

I agree, it would likely break existing code.

> Linus, for context, the other patch in this series saves and restores
> SS.

> Without that, 64-bit sigreturn to a nondefault stack segment is
> basically impossible.

Why would you ever want to do that?

-Andi
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