seg fault on mouse move, run on Linux, display on Cygwin

[Gary]

Symptoms:

I'm running 21.3.50.1 taken directly from savannah.  This version of Emacs
seg faults.  The version that ships with SuSE is 21.3.1 and it gets a
BadWindow (invalid Window parameter) X protocol error rather than a seg fault.

I'm running SuSE 9.1 Linux on my desktop.  My laptop is running Windows XP.
I have Cygwin (www.cygwin.org) installed on the laptop.  I run Cygwin and
start up the XFree86 X display.  Then I run Emacs on the desktop machine
with $DISPLAY set to point to my laptop.  The Emacs window comes up on the
laptop.  The easiest way to reproduce the problem is to run "emacs -q" and
when the window comes up click down with button 1.  This makes the Gnu Emacs
display go away and the underlying *scratch* buffer is displayed.  With the
mouse button still held down, move the mouse.  The amount of movement
doesn't seem to matter.  Alternatively, click once and then click and drag
the mouse.  It seems to be the movement that matters.  You can click around
the *scratch* buffer any number of times as long as you don't move the mouse
while the button is still down.

Running under gdb the stack trace at the time of the seg fault is:

M-x gdb
gdb --annotate=3 emacs

Current directory is ~/foo.emacs/emacs/
GNU gdb 6.1
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i586-suse-linux"...

Using host libthread_db library "/lib/tls/libthread_db.so.1".

(gdb) run -q
Detaching after fork from child process 5906.

Program received signal SIGSEGV, Segmentation fault.
0x6e2a722a in ?? ()
(gdb) bt
#0  0x6e2a722a in ?? ()
#1  0x4025e5af in _X11TransWrite () from /usr/X11R6/lib/libX11.so.6
#2  0x40241766 in _XFlushInt () from /usr/X11R6/lib/libX11.so.6
#3  0x4024181a in _XReply () from /usr/X11R6/lib/libX11.so.6
#4  0x4023bbd4 in XSync () from /usr/X11R6/lib/libX11.so.6
#5  0x080c751d in x_catch_errors_unwind (old_val=140114637) at xterm.c:7611
#6  0x0814cd8f in unbind_to (count=24, value=138285073) at eval.c:3095
#7  0x080c7b1d in x_connection_closed (dpy=0x86209d8, error_message=Variable 
"error_message" is not available.
) at xterm.c:7802
#8  0x080c807f in x_error_handler (display=0x86209d8, error=0xbfffdbd0) at 
xterm.c:7840
#9  0x4023feac in _XError () from /usr/X11R6/lib/libX11.so.6
#10 0x402419b6 in _XReply () from /usr/X11R6/lib/libX11.so.6
#11 0x4023619a in XQueryPointer () from /usr/X11R6/lib/libX11.so.6
#12 0x080c814a in XTmouse_position (fp=0xbfffde34, insist=0, 
bar_window=0xbfffde38, part=0xbfffde3c, x=0xbfffde40, y=0xbfffde44, 
time=0xbfffde48) at xterm.c:3726
#13 0x080f53d5 in read_char (commandflag=0, nmaps=0, maps=0x0, 
prev_event=138285121, used_mouse_menu=0x0) at keyboard.c:4145
#14 0x08168920 in read_filtered_event (no_switch_frame=0, ascii_required=0, 
error_nonascii=0, input_method=0) at lread.c:468
#15 0x08168ae2 in Fread_event (prompt=138285073, inherit_input_method=17285634) 
at lread.c:566
#16 0x0814e99e in Ffuncall (nargs=1, args=0xbfffe140) at eval.c:2747
#17 0x0817ae5f in Fbyte_code (bytestr=136748923, vector=136749188, maxdepth=48) 
at bytecode.c:689
#18 0x0814df3a in Feval (form=136748909) at eval.c:2101
#19 0x0814e251 in Fprogn (args=140644256) at eval.c:408
#20 0x080f15fb in Ftrack_mouse (args=136748901) at keyboard.c:3464
#21 0x0814e005 in Feval (form=136748893) at eval.c:2038
#22 0x0814e251 in Fprogn (args=140644256) at eval.c:408
#23 0x0814e512 in funcall_lambda (fun=136748864, nargs=0, 
arg_vector=0xbfffe454) at eval.c:2916
#24 0x0814e813 in Ffuncall (nargs=1, args=0xbfffe450) at eval.c:2793
#25 0x0817ae5f in Fbyte_code (bytestr=136747851, vector=136748548, maxdepth=56) 
at bytecode.c:689
#26 0x0814e490 in funcall_lambda (fun=136748548, nargs=1, 
arg_vector=0xbfffe564) at eval.c:2923
#27 0x0814e813 in Ffuncall (nargs=2, args=0xbfffe560) at eval.c:2793
#28 0x0817ae5f in Fbyte_code (bytestr=136747067, vector=136747156, maxdepth=40) 
at bytecode.c:689
#29 0x0814e490 in funcall_lambda (fun=136747156, nargs=1, 
arg_vector=0xbfffe6a4) at eval.c:2923
#30 0x0814e813 in Ffuncall (nargs=2, args=0xbfffe6a0) at eval.c:2793
#31 0x0814b7c3 in Fcall_interactively (function=140363385, 
record_flag=17285634, keys=138341932) at callint.c:863
#32 0x080ed95e in Fcommand_execute (cmd=140363385, record_flag=138285073, 
keys=138285073, special=138285073) at keyboard.c:9721
#33 0x080f8c74 in command_loop_1 () at keyboard.c:1776
#34 0x0814d7bd in internal_condition_case (bfun=0x80f8880 <command_loop_1>, 
handlers=138346001, hfun=0x80f32e0 <cmd_error>) at eval.c:1346
#35 0x080f25cc in command_loop_2 () at keyboard.c:1306
#36 0x0814d89a in internal_catch (tag=140644664, func=0x80f25b0 
<command_loop_2>, arg=138285073) at eval.c:1107
#37 0x080f2fc6 in command_loop () at keyboard.c:1285
#38 0x080f3062 in recursive_edit_1 () at keyboard.c:978
#39 0x080f317f in Frecursive_edit () at keyboard.c:1039
#40 0x080e9e41 in main (argc=2, argv=0xbfffeea4) at emacs.c:1687
(gdb) 


In GNU Emacs 21.3.50.1 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2004-08-23 on smbear
configured using `configure '--prefix=/usr''

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
  locale-coding-system: utf-8
  default-enable-multibyte-characters: nil

Major mode: Info

Minor modes in effect:
  auto-compression-mode: t
  encoded-kbd-mode: t
  font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t

Recent input:
l RET c d RET c d SPC f o o . e m TAB e m TAB RET C-z 
/ i m b u g s RET m e m a c s RET DEL DEL DEL DEL DEL 
DEL DEL DEL DEL DEL e m a c s RET m b u g RET C-n C-n 
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-p m RET n 
ESC x r e p SPC o TAB r t - e m TAB RET

Recent messages:
Loading info...
Loading easymenu...done
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Composing main Info directory...
Mark set
Composing main Info directory...done
Making completion list...
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