GNU bug report logs - #7082
24.0.50; Bug in src/doc.c (Fsnarf_documentation)

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

From: Ari Roponen <ari.roponen <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: 24.0.50; Bug in src/doc.c (Fsnarf_documentation)
Date: Tue, 21 Sep 2010 17:39:31 +0300

Hi,

recently compiling Emacs has not worked for me. The compilation always
aborts with this error:

  Loading emacs-lisp/float-sup...
  Loading vc/vc-hooks...
  Loading vc/ediff-hook...
  Loading tooltip...
  Finding pointers to doc strings...
  /bin/sh: line 8: 10391 Segmentation fault      (core dumped) LC_ALL=C `/bin/pwd`/temacs -batch -l loadup dump
  make[1]: *** [emacs] Error 1
  make[1]: Leaving directory `/usr/local/repos/emacs.git/src'
  make: *** [src] Error 2

After some debugging, I may have found the cause. I added an assert to
Fsnarf_documentation in src/doc.c just before the memcpy and it failed:

  Assertion `buf + filled < end' failed.

This means we should use memmove instead, as it can handle overlapping
regions properly.


2010-09-21  Ari Roponen  <ari.roponen <at> gmail.com>  (tiny change)

	* doc.c (Fsnarf_documentation): Use memmove instead of memcpy as
	the regions may overlap.


diff --git a/src/doc.c b/src/doc.c
index f8ab9d0..36f7c0e 100644
--- a/src/doc.c
+++ b/src/doc.c
@@ -678,7 +678,7 @@ the same file name is found in the `doc-directory'.  */)
 	}
       pos += end - buf;
       filled -= end - buf;
-      memcpy (buf, end, filled);
+      memmove (buf, end, filled);
     }
   emacs_close (fd);
   return Qnil;


In GNU Emacs 24.0.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.90.5)
 of 2010-09-21 on arirop
Windowing system distributor `Fedora Project', version 11.0.10899905
configured using `configure  '--with-x-toolkit=gtk3' '--with-imagemagick''

-- 
Ari Roponen

Message #10 received at 7082-done <at> debbugs.gnu.org (full text, mbox):

From: Andreas Schwab <schwab <at> linux-m68k.org>
To: Ari Roponen <ari.roponen <at> gmail.com>
Cc: 7082-done <at> debbugs.gnu.org
Subject: Re: bug#7082: 24.0.50; Bug in src/doc.c (Fsnarf_documentation)
Date: Tue, 21 Sep 2010 21:37:29 +0200

Ari Roponen <ari.roponen <at> gmail.com> writes:

> 2010-09-21  Ari Roponen  <ari.roponen <at> gmail.com>  (tiny change)
>
> 	* doc.c (Fsnarf_documentation): Use memmove instead of memcpy as
> 	the regions may overlap.

Thanks, installed.

Andreas.

-- 
Andreas Schwab, schwab <at> linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

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