GNU bug report logs - #15344
24.3; Crash when yanking in c-mode

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 15344 in the body.
You can then email your comments to 15344 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Lars Ljung <lars <at> matholka.se>
To: bug-gnu-emacs <at> gnu.org
Subject: 24.3; Crash when yanking in c-mode
Date: Wed, 11 Sep 2013 21:15:23 +0200

[Message part 1 (text/plain, inline)]

This bug report will be sent to the Bug-GNU-Emacs mailing list
and the GNU bug tracker at debbugs.gnu.org.  Please check that
the From: line contains a valid email address.  After a delay of up
to one day, you should receive an acknowledgment at that address.

Please write in English if possible, as the Emacs maintainers
usually do not have translators for other languages.

Please describe exactly what actions triggered the bug, and
the precise symptoms of the bug.  If you can, give a recipe
starting from `emacs -Q':

Emacs crashes with segmentation fault. Follow these steps to reproduce:

1) Run emacs -Q
2) Open new buffer in c-mode
3) Enter this:

int test(int *p);
#define TEST(p)

4) copy the first line and yank it at the end of the second line
5) Segmentation fault

The backtrace is attached.


If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
/home/llj/tmp/emacs/emacs-24/etc/DEBUG.


In GNU Emacs 24.3.14 (x86_64-unknown-linux-gnu, GTK+ Version 3.6.4)
 of 2013-09-11 on kvarnholmen
Bzr revision: 111403 rgm <at> gnu.org-20130823165039-x42fumaeambe7mqh
Windowing system distributor `The X.Org Foundation', version 11.0.11303000
System Description:	Ubuntu 13.04

Configured using:
 `configure 'CFLAGS=-O0 -g3''

Important settings:
  value of $LC_COLLATE: sv_SE.UTF-8
  value of $LC_CTYPE: sv_SE.UTF-8
  value of $LC_MESSAGES: sv_SE.UTF-8
  value of $LANG: sv_SE.UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<down> M-x r e p o <tab> r <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
byte-code: End of buffer
Making completion list...

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils help-mode easymenu time-date tooltip ediff-hook
vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list newcomment lisp-mode register page
menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core frame cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese hebrew greek
romanian slovak czech european ethiopic indian cyrillic chinese
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote make-network-process dbusbind dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty emacs)

[gdb-emacs.txt (text/plain, attachment)]

Message #8 received at 15344 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ljung <lars <at> matholka.se>
To: 15344 <at> debbugs.gnu.org
Subject: Re: bug#15344: Acknowledgement (24.3; Crash when yanking in c-mode)
Date: Fri, 13 Sep 2013 22:53:23 +0200

Using --enable-checking I also got this:

textprop.c:1549: Emacs fatal error: assertion failed: i != 0

That seems to be the cause of the segmentation fault. Let me know if
there is anything else I can do to debug this.

Also, I can reproduce this on trunk.

Regards,
Lars Ljung

Message #11 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Alan Mackenzie <acm <at> muc.de>
To: gnu-emacs-bug <at> moderators.isc.org
Subject: Re: bug#15344: Acknowledgement (24.3; Crash when yanking in c-mode)
Date: Sat, 14 Sep 2013 09:31:41 +0000 (UTC)

Lars Ljung <lars <at> matholka.se> wrote:
> Using --enable-checking I also got this:

> textprop.c:1549: Emacs fatal error: assertion failed: i != 0

> That seems to be the cause of the segmentation fault. Let me know if
> there is anything else I can do to debug this.

> Also, I can reproduce this on trunk.

I confirm that the segfault happens to me too, on Emacs 24.3 running
on GNU/Linux.

I can't see at the moment that it's directly related to CC Mode, though.

> Regards,
> Lars Ljung

-- 
Alan Mackenzie (Nuremberg, Germany).

Message #14 received at 15344 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: 15344 <at> debbugs.gnu.org
Subject: Re: 24.3; Crash when yanking in c-mode
Date: Sun, 22 Sep 2013 00:40:35 -0700

For what it's worth, I can't reproduce the problem on
my platform (Fedora 19 x86-64), either with the bundled
Emacs 24.3, or with the current trunk (bzr 114425).
Perhaps I'm not cutting or pasting properly....

Message #17 received at 15344 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ljung <lars <at> matholka.se>
To: 15344 <at> debbugs.gnu.org
Subject: Re: 24.3; Crash when yanking in c-mode
Date: Sun, 22 Sep 2013 20:10:54 +0200

Maybe this is a better way to describe how to reproduce the segfault:

Start with emacs -Q

C-x b * t e s t * <return> M-x c - m o d e <return>
i n t SPC t e s t ( i n t SPC * p ) ; C-SPC M-b M-b
M-b M-w C-e <return> # d e f i n e SPC T E S T ( p
) SPC C-y

I've had a look at the code but unfortunately I don't have enough
knowledge about the Emacs internals to understand what's going on.

Regards,
Lars Ljung

Message #20 received at 15344 <at> debbugs.gnu.org (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
To: Lars Ljung <lars <at> matholka.se>
Cc: 15344 <at> debbugs.gnu.org
Subject: Re: bug#15344: 24.3; Crash when yanking in c-mode
Date: Thu, 10 Oct 2013 17:18:34 -0400

Lars Ljung wrote:

> Maybe this is a better way to describe how to reproduce the segfault:
>
> Start with emacs -Q
>
> C-x b * t e s t * <return> M-x c - m o d e <return>
> i n t SPC t e s t ( i n t SPC * p ) ; C-SPC M-b M-b
> M-b M-w C-e <return> # d e f i n e SPC T E S T ( p
> ) SPC C-y

Yes, that crashes 24.3 and current trunk for me too.

Some resemblence to http://debbugs.gnu.org/13743 ?

Message #25 received at 15344 <at> debbugs.gnu.org (full text, mbox):

From: Thien-Thi Nguyen <ttn <at> gnu.org>
To: 15344 <at> debbugs.gnu.org
Cc: Lars Ljung <lars <at> matholka.se>
Subject: Re: bug#15344: 24.3; Crash when yanking in c-mode
Date: Mon, 13 Jan 2014 14:39:34 +0100

[Message part 1 (text/plain, inline)]

Here is a script to make debugging easier:

[reproduce-15344.el (application/emacs-lisp, attachment)]

[Message part 3 (text/plain, inline)]

FYI, it still manifests on trunk as of 2014-01-11.

-- 
Thien-Thi Nguyen
   GPG key: 4C807502
   (if you're human and you know it)
      read my lisp: (responsep (questions 'technical)
                               (not (via 'mailing-list)))
                     => nil

[Message part 4 (application/pgp-signature, inline)]

Message #28 received at 15344 <at> debbugs.gnu.org (full text, mbox):

From: Daniel Colascione <dancol <at> dancol.org>
To: Thien-Thi Nguyen <ttn <at> gnu.org>, 15344 <at> debbugs.gnu.org
Cc: Lars Ljung <lars <at> matholka.se>
Subject: Re: bug#15344: 24.3; Crash when yanking in c-mode
Date: Mon, 13 Jan 2014 05:59:33 -0800

On 01/13/2014 05:39 AM, Thien-Thi Nguyen wrote:
> Here is a script to make debugging easier:

Thanks. Does this patch have any unwanted side effects? It seems 
perfectly reasonable to me that we could reach the end of the interval 
tree without finding anything to modify or going past our bound.

=== modified file 'src/textprop.c'
--- src/textprop.c	2014-01-01 07:43:34 +0000
+++ src/textprop.c	2014-01-13 13:56:18 +0000
@@ -1741,6 +1741,8 @@
 	}
       len -= LENGTH (i);
       i = next_interval (i);
+      if (!i)
+        return Qnil;
     }
 }

Message #31 received at 15344 <at> debbugs.gnu.org (full text, mbox):

From: Daniel Colascione <dancol <at> dancol.org>
To: Thien-Thi Nguyen <ttn <at> gnu.org>, 15344 <at> debbugs.gnu.org
Cc: Lars Ljung <lars <at> matholka.se>
Subject: Re: bug#15344: 24.3; Crash when yanking in c-mode
Date: Mon, 13 Jan 2014 06:11:29 -0800

On 01/13/2014 05:59 AM, Daniel Colascione wrote:
> On 01/13/2014 05:39 AM, Thien-Thi Nguyen wrote:
>> Here is a script to make debugging easier:
>
> Thanks. Does this patch have any unwanted side effects? It seems
> perfectly reasonable to me that we could reach the end of the interval
> tree without finding anything to modify or going past our bound.
>
> === modified file 'src/textprop.c'

Actually, you probably want this one.

=== modified file 'src/textprop.c'
--- src/textprop.c	2014-01-01 07:43:34 +0000
+++ src/textprop.c	2014-01-13 14:07:21 +0000
@@ -1741,6 +1741,17 @@
 	}
       len -= LENGTH (i);
       i = next_interval (i);
+      if(!i)
+        if (modified)
+          {
+            if (BUFFERP (object))
+              signal_after_change (XINT (start),
+                                   XINT (end) - XINT (start),
+                                   XINT (end) - XINT (start));
+            return Qt;
+          }
+        else
+          return Qnil;
     }
 }

Message #34 received at 15344 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Daniel Colascione <dancol <at> dancol.org>
Cc: ttn <at> gnu.org, lars <at> matholka.se, 15344 <at> debbugs.gnu.org
Subject: Re: bug#15344: 24.3; Crash when yanking in c-mode
Date: Mon, 13 Jan 2014 18:19:48 +0200

> Date: Mon, 13 Jan 2014 06:11:29 -0800
> From: Daniel Colascione <dancol <at> dancol.org>
> Cc: Lars Ljung <lars <at> matholka.se>
> 
> +      if(!i)
> +        if (modified)
> +          {
> +            if (BUFFERP (object))
> +              signal_after_change (XINT (start),
> +                                   XINT (end) - XINT (start),
> +                                   XINT (end) - XINT (start));
> +            return Qt;
> +          }
> +        else
> +          return Qnil;
>       }

Doesn't this give you a warning about ambiguous else?

Message #37 received at 15344 <at> debbugs.gnu.org (full text, mbox):

From: Daniel Colascione <dancol <at> dancol.org>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: ttn <at> gnu.org, lars <at> matholka.se, 15344 <at> debbugs.gnu.org
Subject: Re: bug#15344: 24.3; Crash when yanking in c-mode
Date: Mon, 13 Jan 2014 10:33:46 -0800

On 01/13/2014 08:19 AM, Eli Zaretskii wrote:
>> Date: Mon, 13 Jan 2014 06:11:29 -0800
>> From: Daniel Colascione <dancol <at> dancol.org>
>> Cc: Lars Ljung <lars <at> matholka.se>
>>
>> +      if(!i)
>> +        if (modified)
>> +          {
>> +            if (BUFFERP (object))
>> +              signal_after_change (XINT (start),
>> +                                   XINT (end) - XINT (start),
>> +                                   XINT (end) - XINT (start));
>> +            return Qt;
>> +          }
>> +        else
>> +          return Qnil;
>>        }
>
> Doesn't this give you a warning about ambiguous else?
>

It does when I turn on warnings, yes. :-) I'll add braces when I check 
it in.

Message #42 received at 15344-done <at> debbugs.gnu.org (full text, mbox):

From: Daniel Colascione <dancol <at> dancol.org>
To: 15344-done <at> debbugs.gnu.org
Subject: Done
Date: Mon, 13 Jan 2014 15:42:31 -0800

Done

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.