From: Eli Zaretskii <eliz@gnu.org>
To: Andreas Schwab <schwab@suse.de>
Cc: 23704@debbugs.gnu.org, vincent.belaiche@gmail.com
Subject: bug#23704: 25.1.50; Emacs crash in syntax.c
Date: Mon, 06 Jun 2016 17:52:41 +0300 [thread overview]
Message-ID: <83inxmtlmu.fsf@gnu.org> (raw)
In-Reply-To: <mvmporuu5ug.fsf@hawking.suse.de> (message from Andreas Schwab on Mon, 06 Jun 2016 09:36:07 +0200)
> From: Andreas Schwab <schwab@suse.de>
> Date: Mon, 06 Jun 2016 09:36:07 +0200
> Cc: 23704@debbugs.gnu.org
>
> > 2233 if (! fastmap[SYNTAX (*p)])
>
> I think I have seen a similar crash with the emacs-25 branch as well,
> but only once, and I couldn't reproduce it so far.
If my reading of the code is correct, we have pointers to buffer text
and the gap lying around, while invoking code that can GC (which
compacts buffers). For example, the sequence of calls
SETUP_SYNTAX_TABLE
-> SETUP_BUFFER_SYNTAX_TABLE
-> update_syntax_table_forward
-> parse_sexp_propertize
could call Lisp, and that happens after we already computed the values
of p, endp, and stop. Likewise the call to UPDATE_SYNTAX_TABLE_FORWARD
we make inside the loop.
If GC decides to compact the gap, it could well make a previously
valid pointer invalid.
Could that be the reason?
next prev parent reply other threads:[~2016-06-06 14:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-06 5:25 bug#23704: 25.1.50; Emacs crash in syntax.c Vincent Belaïche
2016-06-06 7:36 ` Andreas Schwab
2016-06-06 14:52 ` Eli Zaretskii [this message]
2016-06-06 15:03 ` Andreas Schwab
2016-06-06 14:49 ` Eli Zaretskii
2016-06-06 16:14 ` Vincent Belaïche
2016-06-06 18:45 ` Eli Zaretskii
2016-06-06 17:17 ` Paul Eggert
2016-06-06 18:58 ` Eli Zaretskii
2016-06-06 20:07 ` Paul Eggert
2016-06-07 2:38 ` Eli Zaretskii
2016-06-07 7:26 ` Paul Eggert
2016-06-07 15:52 ` Eli Zaretskii
2016-06-07 16:36 ` Paul Eggert
2016-06-07 17:17 ` Eli Zaretskii
2016-06-07 21:46 ` Vincent Belaïche
2016-06-07 22:11 ` Paul Eggert
2016-06-08 5:34 ` Vincent Belaïche
2016-06-08 16:41 ` Eli Zaretskii
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