bug#17526: 24.3.90; Crash in Cygwin-w32 build

[Eli Zaretskii]

> Date: Mon, 19 May 2014 15:19:24 -0400
> From: Ken Brown <kbrown@cornell.edu>
> CC: 17526@debbugs.gnu.org
> 
> On 5/19/2014 11:18 AM, Eli Zaretskii wrote:
> >> Date: Mon, 19 May 2014 08:30:49 -0400
> >> From: Ken Brown <kbrown@cornell.edu>
> >>
> >> I just got a crash with the following backtrace:
> >>
> >> #0  0x000007fefd5f3ca3 in KERNELBASE!DebugBreak ()
> >>     from /c/Windows/system32/KERNELBASE.dll
> >> #1  0x000000010061a344 in emacs_abort ()
> >>      at /usr/src/debug/emacs-24.3.90-1/src/w32fns.c:8460
> >> #2  0x000000010043616a in move_it_to (it=0x4284e0, to_charpos=-1, to_x=-1,
> >>      to_y=-1, to_vpos=10, op=4)
> >>      at /usr/src/debug/emacs-24.3.90-1/src/xdisp.c:9198
> >> #3  0x0000000100436fc2 in move_it_by_lines (it=0x4284e0, dvpos=10)
> >>      at /usr/src/debug/emacs-24.3.90-1/src/xdisp.c:9490
> >
> > That's a weird crash.  Any chance of a reproducible recipe?
> 
> No, I wasn't doing anything out of the ordinary -- just scrolling 
> through a plain text file.

Well, maybe try scrolling more than usual in the future, perhaps you
will hit it again.

> There have been other weird crashes reported 
> for the Cygwin-w32 build, such as this one that was sent to the Cygwin 
> mailing list this morning:
> 
>    https://cygwin.com/ml/cygwin/2014-05/msg00396.html

That crash makes no sense, arithcompare can only abort if its 3rd
argument is something other than the 6 enumeration values.  I suspect
that was an optimized build (although I see no "optimized out" values
in the backtrace).

> >    skip
> >    it->current
> >    it->current_x
> >    it->current_y
> >    it->vpos
> >
> > Also, what text is there in the window where the scroll command was
> > attempted, starting from the text position in it->current.pos.charpos
> > and for 10 screen lines down?
> 
> Unfortunately, my computer spontaneously rebooted while installing some 
> software, without giving me a chance to say "reboot later".  So I have 
> no information, and there's probably no more we can do with this bug.

Too bad.