GNU bug report logs - #17168
24.3.50; Segfault at mark_object

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Package: emacs;

Reported by: Nicolas Richard <theonewiththeevillook <at> yahoo.fr>

Date: Wed, 2 Apr 2014 07:45:05 UTC

Severity: important

Tags: moreinfo

Merged with 15583, 15688, 15719, 15972, 16278, 16521, 17167, 17184

Found in version 24.3.50

Done: Stefan Monnier <monnier <at> IRO.UMontreal.CA>

Bug is archived. No further changes may be made.

Full log

Message #63 received at 17168 <at> debbugs.gnu.org (full text, mbox):

From: Dmitry Antipov <dmantipov <at> yandex.ru>
To: Daniel Colascione <dancol <at> dancol.org>
Cc: 17168 <at> debbugs.gnu.org
Subject: Re: bug#17168: 24.3.50; Segfault at mark_object
Date: Thu, 03 Apr 2014 18:03:05 +0400

[Message part 1 (text/plain, inline)]
On 04/03/2014 01:08 PM, Daniel Colascione wrote:

> Found the bug: that symbol's name is in pure storage, so we ignore the
> value of sym->s.gcmarkbit and assume the symbol is always live: we
> never put it on the free list, so we never set its function slot to
> Vdead. Later, during another GC pass, conservative GC scanning happens
> to find a pointer to the symbol. We begin marking it, descend into the
> function slot, which is still pointing to the old, dead object value. We
> try to mark memory being used for some other purpose and enter la-la land.

What about this workaround? Until we find a better solution,
this should prevent crashes at least.

Dmitry

[bug17168_workaround.patch (text/x-patch, attachment)]
This bug report was last modified 11 years and 47 days ago.

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