GNU bug report logs - #29843
25.3; Emacs crash when running emacsclient

Previous Next

Full log

Message #8 received at 29843 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Mike Kupfer <mkupfer <at> alum.berkeley.edu>
Cc: 29843 <at> debbugs.gnu.org
Subject: Re: bug#29843: 25.3; Emacs crash when running emacsclient
Date: Mon, 25 Dec 2017 18:03:41 +0200

> From: Mike Kupfer <mkupfer <at> alum.berkeley.edu>
> Date: Sun, 24 Dec 2017 12:29:06 -0800
> 
> I ran "emacsclient -c" to get a new Emacs frame on a system running MATE
> on Debian 9.  IIRC, a new frame appeared for a split second and then
> disappeared.  (I'm afraid the crash happened a few days ago and I'm just
> now getting to filing the bug report.)  I found a core file; gdb says
> there was a segmentation fault.  This is the first and only time I've
> seen such a crash.
> 
> I'll hold onto the core file for a couple weeks in case there is
> additional information to extract from it.
> 
> (gdb) bt full
> #0  0x00007f0441b83f9f in raise () from /lib/x86_64-linux-gnu/libpthread.so.0
> No symbol table info available.
> #1  0x00000000004d99d1 in terminate_due_to_signal (sig=sig <at> entry=11, 
>     backtrace_limit=backtrace_limit <at> entry=40) at emacs.c:381
> No locals.
> #2  0x00000000004f14ce in handle_fatal_signal (sig=sig <at> entry=11)
>     at sysdep.c:1601
> No locals.
> #3  0x00000000004f16d9 in deliver_thread_signal (sig=sig <at> entry=11, 
>     handler=0x4f14c0 <handle_fatal_signal>) at sysdep.c:1575
> No locals.
> #4  0x00000000004f173f in deliver_fatal_thread_signal (sig=11) at sysdep.c:1613
> No locals.
> #5  handle_sigsegv (sig=11, siginfo=<optimized out>, arg=<optimized out>)
>     at sysdep.c:1695
>         fatal = <optimized out>
> #6  <signal handler called>
> No symbol table info available.
> #7  reconsider_clip_changes (w=w <at> entry=0x3764378) at xdisp.c:13452

This segfault is here:

  static void
  reconsider_clip_changes (struct window *w)
  {
    struct buffer *b = XBUFFER (w->contents);

    if (b->clip_changed
	&& w->window_end_valid
	&& w->current_matrix->buffer == b
	&& w->current_matrix->zv == BUF_ZV (b)
	&& w->current_matrix->begv == BUF_BEGV (b))   <<<<<<<<<<<<<<<<<<
      b->clip_changed = false;

So either w or b is a NULL or garbled pointer.  Can you tell which
one?  (Let me know if you need help with GDB commands to do that.)

Thanks.

Previous Next

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