menubar segfault

[Scott Lanning]

This maybe an unlikely case for a user, but here goes anyway.

Using
`GNU Emacs 21.1.50.15 (i686-pc-linux-gnu, X toolkit,
Xaw3d scroll bars)', but not the last release 21.1.1,
I found by accident that the following will cause a segfault.
(I hope my little patchette didn't cause it... :/
Sorry, I didn't try to revert it yet.)
    If I first select a menubar item so that a
menu appears, then (how to explain this...?) swirl the
mouse around vigorously such that different menus will
pop up and different items in those menus are selected,
after some random time (sorry I couldn't isolate yet exactly
what sequence of events triggers it) it will segfault.
Something weird is that `gdb` says it segfaults in different
functions (so far: x_free_colors, x_set_border_pixel,
init_iterator, and compute_tip_xy (not shown)).
Here are several examples (some redundant stuff trimmed away):

1.
(gdb) run
Starting program: /usr/local/src/emacs/src/emacs -geometry 80x40+0+0

Program received signal SIGSEGV, Segmentation fault.
0x809f26f in x_free_colors (f=0x84b9538, pixels=0xbfffd714, npixels=1)
    at xfaces.c:708
(gdb) c

2.
(gdb) run
Program received signal SIGSEGV, Segmentation fault.
0x80c62d4 in x_set_border_pixel (f=0x859aa30, pix=0) at xfns.c:1713
(gdb) c

3.
(gdb) run
Program received signal SIGSEGV, Segmentation fault.
0x80c62d4 in x_set_border_pixel (f=0x85f0d40, pix=0) at xfns.c:1713

4.
(gdb) run
Program received signal SIGSEGV, Segmentation fault.
0x805f476 in init_iterator (it=0xbfffda70, w=0x83d0fd8, charpos=1,
bytepos=1,
    row=0x8529908, base_face_id=DEFAULT_FACE_ID) at xdisp.c:855

5.
(gdb) run
Program received signal SIGSEGV, Segmentation fault.
0x805f476 in init_iterator (it=0xbfffda70, w=0x8593988, charpos=1,
bytepos=1,
    row=0x85896a0, base_face_id=DEFAULT_FACE_ID) at xdisp.c:855

6.
(gdb) run
Program received signal SIGSEGV, Segmentation fault.
0x80c62d4 in x_set_border_pixel (f=0x859d660, pix=0) at xfns.c:1713
(gdb) c