GNU bug report logs - #18410
Use SAFE_ALLOCA etc. to avoid unbounded stack allocation.

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Message #49 received at 18410 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 18410 <at> debbugs.gnu.org
Subject: Re: bug#18410: Use SAFE_ALLOCA etc. to avoid unbounded stack
 allocation.
Date: Sun, 07 Sep 2014 19:38:17 -0700

Stefan Monnier wrote:
> MAX_ALLOCA is chosen small so that we can allocate several/many objects
> of size MAX_ALLOCA.

That's one reason, but another is that stack-overflow checking often 
relies on guard pages.  If we blindly increase MAX_ALLOCA (or some 
variant of it, just for call-process) Emacs could bypass stack-overflow 
checking, resulting in behavior that could be worse than simply dumping 
core.

If I understand things correctly, Dmitry's recent stack-overflow changes 
don't affect this, as they don't deal with the guard-page region size.

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