[debbugs-tracker] bug#9495: closed (24.0.50; Segfault in try_cursor_movement)

[GNU bug Tracking System]

Your message dated Thu, 15 Sep 2011 19:05:20 +0300
with message-id <address@hidden>
and subject line Re: bug#9495: 24.0.50; Segfault in try_cursor_movement
has caused the debbugs.gnu.org bug report #9495,
regarding 24.0.50; Segfault in try_cursor_movement
to be marked as done.

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-- 
9495: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=9495
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> --- Begin Message ---
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> Subject: 
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> 24.0.50; Segfault in try_cursor_movement
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> Date: 
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> Tue, 13 Sep 2011 21:28:17 +0200
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> User-agent: 
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> Gnus/5.13 (Gnus v5.13) Emacs/24.0.50 (gnu/linux)
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> Program terminated with signal 11, Segmentation fault.
> #0  0x00007f5bccbe6fe7 in kill () at ../sysdeps/unix/syscall-template.S:82
> 82      ../sysdeps/unix/syscall-template.S: No such file or directory.
>         in ../sysdeps/unix/syscall-template.S
> (gdb) bt
> #0  0x00007f5bccbe6fe7 in kill () at ../sysdeps/unix/syscall-template.S:82
> #1  0x000000000056e889 in fatal_error_signal (sig=11) at emacs.c:358
> #2  <signal handler called>
> #3  0x0000000000465f3f in try_cursor_movement (window=20987605, startp=...,
>     scroll_step=0x7fff5e400758) at xdisp.c:14639
>
> xdisp.c:14639: (BUFFERP (g->object) && g->charpos == PT)
>
> g is not a valid glyph here.
>
> (gdb) p MATRIX_ROW (w->current_matrix, w->cursor.vpos).used[TEXT_AREA]
> $3 = 80
> (gdb) p w->cursor.hpos
> $4 = 80
>
>
> 2011-09-13  Johan Bockgård  <address@hidden>
>
>         * xdisp.c (try_cursor_movement): Check bounds of hpos.
>
> === modified file 'src/xdisp.c'
> --- src/xdisp.c 2011-09-09 01:06:52 +0000
> +++ src/xdisp.c 2011-09-11 15:03:56 +0000
> @@ -14627,7 +14627,11 @@ try_cursor_movement (Lisp_Object window,
>                      is set, we are done.  */
>                   at_zv_p =
>                     MATRIX_ROW (w->current_matrix, 
> w->cursor.vpos)->ends_at_zv_p;
> -                 if (!at_zv_p)
> +                 if (!at_zv_p
> +                     && w->cursor.hpos >= 0
> +                     && (w->cursor.hpos
> +                         < MATRIX_ROW_USED (w->current_matrix,
> +                                            w->cursor.vpos)))
>                     {
>                       struct glyph_row *candidate =
>                         MATRIX_ROW (w->current_matrix, w->cursor.vpos);
>
>
> BTW, is this code in try_window_reusing_current_matrix correct?
>
>     struct glyph *glyph = row->glyphs[TEXT_AREA] + w->cursor.hpos;
>     struct glyph *end = glyph + row->used[TEXT_AREA];
>
> It doesn't seem right for end to depend on hpos.
>
>
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> --- End Message ---
> --- Begin Message ---
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> Subject: 
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> Re: bug#9495: 24.0.50; Segfault in try_cursor_movement
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>
>
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> Date: 
>
> Thu, 15 Sep 2011 19:05:20 +0300
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>
>
>
> > From: Johan Bockgård <address@hidden>
> > Cc: address@hidden
> > Date: Wed, 14 Sep 2011 21:50:29 +0200
> > 
> > emacs -Q -eval '(setq line-move-visual nil truncate-lines t track-eol t)'
> > 
> > C-u 100 x RET
> > y <up>
> > 
> > At this point, in try_cursor_movement, point is in the "x" line, the
> > window has not yet hscrolled, and the value of hpos is just after the
> > last valid element in glyphs[TEXT_AREA].
> > 
> > (It only actually crashes some of the time, of course.)
>
> Thanks, I committed your patch with a minor variation.
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> --- End Message ---