GNU bug report logs - #18361
New 'sort' implementation can crash Emacs

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Package: emacs;

Reported by: Paul Eggert <eggert <at> cs.ucla.edu>

Date: Fri, 29 Aug 2014 21:26:01 UTC

Severity: minor

Done: Paul Eggert <eggert <at> cs.ucla.edu>

Bug is archived. No further changes may be made.

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From: Dmitry Antipov <dmantipov <at> yandex.ru>
To: Paul Eggert <eggert <at> cs.ucla.edu>
Cc: 18361 <at> debbugs.gnu.org
Subject: bug#18361: New 'sort' implementation can crash Emacs
Date: Sat, 30 Aug 2014 02:47:01 +0400

On 08/30/2014 01:24 AM, Paul Eggert wrote:

> The new implementation of 'sort' in the trunk invokes qsort (or qsort_r),
> but these functions have undefined behavior if the comparison function is
> ill-behaved.  Since the comparison predicate is user-defined, this means
> a bad user-supplied comparison function could crash Emacs.

I don't see how is that possible if we operate on a correctly initialized
vector and sort_vector_predicate is a valid function accepting 2 arguments.
Can you provide an example?  Is that just a poor property of the particular
qsort(_r) implementation?

Dmitry
This bug report was last modified 10 years and 347 days ago.

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