linux-kernel - Re: [PATCH v2 24/39] x86/cet/shstk: Add user-mode shadow stack support

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Message-ID: <202210201553.8CE1524C5@keescook>
Date:   Thu, 20 Oct 2022 15:54:49 -0700
From:   Kees Cook <keescook@...omium.org>
To:     "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
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Subject: Re: [PATCH v2 24/39] x86/cet/shstk: Add user-mode shadow stack
 support

On Thu, Oct 20, 2022 at 09:29:38PM +0000, Edgecombe, Rick P wrote:
> The code used to use shstk->base and shstk->size to keep track of if
> shadow stack was enabled. I'm not sure why to zero it now. Just
> defensively or did you see a concrete issue?

Just to be defensive. It's not fast path by any means, to better to
have values that make a bit of sense there. *shrug* It just stood out
as feeling "missing" while I was reading the code.

-- 
Kees Cook