bug#34394: 27.0.50; Emacs segfaults with SLY, company and C-g

[João Távora]

Thanks! Will do.

If it works, can this please make it to Emacs 26.2?

João

On Tue, Feb 12, 2019 at 5:25 PM Eli Zaretskii <eliz@gnu.org> wrote:
>
> > Date: Sun, 10 Feb 2019 18:42:40 +0200
> > From: Eli Zaretskii <eliz@gnu.org>
> > Cc: 34394@debbugs.gnu.org
> >
> > >   src/emacs -Q -L path/to/company-mode -l company -l foo.el -f 
> > > foo-test-bug
> >
> > Thanks, this reproduces the problem with 100% probability, and I'm
> > looking into the problem.
>
> I think I found the culprit.  Please see if the patch below fixes the
> problem, including the one you had in the real-life scenario and
> environment.
>
> diff --git a/src/keyboard.c b/src/keyboard.c
> index 49c687f..f6550f7 100644
> --- a/src/keyboard.c
> +++ b/src/keyboard.c
> @@ -365,6 +365,7 @@ static Lisp_Object make_lispy_focus_out (Lisp_Object);
>  static bool help_char_p (Lisp_Object);
>  static void save_getcjmp (sys_jmp_buf);
>  static void restore_getcjmp (sys_jmp_buf);
> +static void unwind_getcjmp (void *);
>  static Lisp_Object apply_modifiers (int, Lisp_Object);
>  static void restore_kboard_configuration (int);
>  static void handle_interrupt (bool);
> @@ -2144,12 +2145,14 @@ read_event_from_main_queue (struct timespec *end_time,
>      return c;
>
>    /* Actually read a character, waiting if necessary.  */
> +  ptrdiff_t count = SPECPDL_INDEX ();
>    save_getcjmp (save_jump);
> +  record_unwind_protect_ptr (unwind_getcjmp, &save_jump);
>    restore_getcjmp (local_getcjmp);
>    if (!end_time)
>      timer_start_idle ();
>    c = kbd_buffer_get_event (&kb, used_mouse_menu, end_time);
> -  restore_getcjmp (save_jump);
> +  unbind_to (count, Qnil);
>
>    if (! NILP (c) && (kb != current_kboard))
>      {
> @@ -2638,10 +2641,12 @@ read_char (int commandflag, Lisp_Object map,
>         {
>           Lisp_Object tem0;
>
> +         ptrdiff_t count = SPECPDL_INDEX ();
>           save_getcjmp (save_jump);
> +         record_unwind_protect_ptr (unwind_getcjmp, &save_jump);
>           restore_getcjmp (local_getcjmp);
>           tem0 = sit_for (Vecho_keystrokes, 1, 1);
> -         restore_getcjmp (save_jump);
> +         unbind_to (count, Qnil);
>           if (EQ (tem0, Qt)
>               && ! CONSP (Vunread_command_events))
>             echo_now ();
> @@ -2712,10 +2717,12 @@ read_char (int commandflag, Lisp_Object map,
>
>           timeout = min (timeout, MOST_POSITIVE_FIXNUM / delay_level * 4);
>           timeout = delay_level * timeout / 4;
> +         ptrdiff_t count1 = SPECPDL_INDEX ();
>           save_getcjmp (save_jump);
> +         record_unwind_protect_ptr (unwind_getcjmp, &save_jump);
>           restore_getcjmp (local_getcjmp);
>           tem0 = sit_for (make_number (timeout), 1, 1);
> -         restore_getcjmp (save_jump);
> +         unbind_to (count1, Qnil);
>
>           if (EQ (tem0, Qt)
>               && ! CONSP (Vunread_command_events))
> @@ -3329,6 +3336,14 @@ restore_getcjmp (sys_jmp_buf temp)
>  {
>    memcpy (getcjmp, temp, sizeof getcjmp);
>  }
> +
> +static void
> +unwind_getcjmp (void *ptr)
> +{
> +  sys_jmp_buf jbuf;
> +  memcpy (jbuf, *(sys_jmp_buf *)ptr, sizeof getcjmp);
> +  restore_getcjmp (jbuf);
> +}
>
>  /* Low level keyboard/mouse input.
>     kbd_buffer_store_event places events in kbd_buffer, and



-- 
João Távora