bug#24064: 24.5; NULL pointer dereference in compute_motion(), indent.c

[Sergei Litvin]

I've prepared an elisp file to reproduce a crash:

1) Open it and move cursor to the end of the file

2) Execute eval-buffer

3) Press C-l several times


Sergei Litvin


On 07/25/2016 07:24 PM, Eli Zaretskii wrote:
> > From: Sergei Litvin <litvindev@gmail.com>
> > Date: Mon, 25 Jul 2016 02:51:40 +0300
> >
> >
> > struct position *
> > compute_motion (ptrdiff_t from, ptrdiff_t frombyte, EMACS_INT fromvpos,
> > EMACS_INT fromhpos, bool did_motion, ptrdiff_t to,
> > EMACS_INT tovpos, EMACS_INT tohpos, EMACS_INT width,
> > ptrdiff_t hscroll, int tab_offset, struct window *win)
> > {
> >
> > ...
> >
> > if (dp == buffer_display_table ())
> > width_table = (VECTORP (BVAR (current_buffer, width_table))
> > ? XVECTOR (BVAR (current_buffer, width_table))->contents
> > : 0);
> > else
> > /* If the window has its own display table, we can't use the width
> > run cache, because that's based on the buffer's display table. */
> > width_table = 0; // initialize it with 0 (current buffer has no display table)
> >
> > ...
> >
> > if (width_cache)
> > {
> > /* Is this character part of the current run? If so, extend
> > the run. */
> > if (pos - 1 == width_run_end
> > && XFASTINT (width_table[c]) == width_run_width) // dereference width_table 
> > here, and crash
> > width_run_end = pos;
> Did you actually see such a crash, and if so, can you show a recipe
> for reproducing that?
>
> Thanks.

emacs-crash.el
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