Segfault in Emacs 23 with multi-tty

[Daniel Hackney]

While testing the new multi-tty feature, I came across a segfault. I started up
an instance of emacs-snapshot in a terminal with the following command:

 $ emacs-snapshot -q -nw --eval "(setq server-name \"editor\")" -f server-start

I then opened a second terminal and ran:

 $ emacsclient -s editor -e '(ignore)'

The -e '(ignore)' is a no-op to give me a fresh frame. The second command opens
up a GTK frame connected to the first frame and both work just fine. The problem
comes when I try to kill the GTK frame. First, if I use
"save-buffers-kill-terminal", it kills the server in the terminal, which is not
what I want. "delete-frame" seemed to be the best choice. Unfortunately, when I
run "delete-frame" from the GTK frame, not only does the GTK frame close, but
the terminal frame (which is also the server) dies with a segfault:

  Fatal error (11)Segmentation fault (core dumped)

Here is the result of running it in GDB. Not terribly useful, but it might shed
some light on the situation.

#0  0x080d3bca in ?? ()
#1  0x08a13d80 in ?? ()
#2  0x088c4e60 in ?? ()
#3  0xbff3d998 in ?? ()
#4  0x08370868 in ?? ()
#5  0x088c4e60 in ?? ()
#6  0x088c4e64 in ?? ()
#7  0xbff3d9e8 in ?? ()
#8  0x08063062 in ?? ()
#9  0x084bfb28 in ?? ()
#10 0x0834de5d in ?? ()
#11 0x083508c9 in ?? ()
#12 0x083508f9 in ?? ()
#13 0x08062870 in ?? ()
#14 0xb7653170 in ?? () from /lib/tls/i686/cmov/libc.so.6
#15 0x08da9b00 in ?? ()
#16 0x08da9ae8 in ?? ()
#17 0x08903adc in ?? ()
#18 0x08a42c4c in ?? ()
#19 0xb787c8ac in __pthread_mutex_unlock_usercnt ()
   from /lib/tls/i686/cmov/libpthread.so.0
Backtrace stopped: previous frame inner to this frame (corrupt stack?)

If I instead run the client in a tty (by adding the "-t" option), exiting via
both kill-terminal and delete-frame work as expected, killing the current
terminal without killing the server.

The packages I am using were acquired from here:

  http://ppa.launchpad.net/avassalotti/ubuntu

Obviously, the trace will not be of much use without the debugging symbols, but
the installation I used did not include them.

Here is additional information about my version of emacs.

In GNU Emacs 23.0.60.1 (i486-pc-linux-gnu, GTK+ Version 2.12.0)
 of 2007-10-31 on samarium
 (emacs-snapshot package, version 1:20071030-1~gutsy)
Windowing system distributor `The X.Org Foundation', version 11.0.10300000
configured using `configure  '--build' 'i486-linux-gnu' '--host'
'i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib'
'--libexecdir=/usr/lib' '--localstatedir=/var'
'--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes'
'--enable-locallisppath=/etc/emacs-snapshot:/etc/emacs:/usr/local/share/emacs/23.0.60/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.0.60/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/23.0.60/leim'
'--with-x=yes' '--with-x-toolkit=gtk' '--enable-font-backend'
'--with-xft' '--with-freetype' 'build_alias=i486-linux-gnu'
'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN
-DSITELOAD_PURESIZE_EXTRA=5000 -g -O2''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t


-- 
Daniel M. Hackney