Re: MPS: Crash when switching to buffer

[Eli Zaretskii]

> From: Ihor Radchenko <yantar92@posteo.net>
> Cc: emacs-devel@gnu.org, gerd.moellmann@gmail.com, eller.helmut@gmail.com
> Date: Mon, 01 Jul 2024 12:13:25 +0000
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > This is not a crash when switching buffers, this is a crash in
> > redisplay, when merging faces for display.
> >
> > What exactly is the cause of segfault in plist_get?  Please look at
> > the data there in the debugger and see which one(s) are invalid or
> > corrupted.  From the backtrace it sounds like the plist of the face is
> > botched, but that's a guess.
> 
> May you please provide more detailed instructions?

Below.

> > Is this reproducible? I tried switching between two buffers and didn't
> > get any crashes here, FWIW.
> 
> I've seen it multiple times after a few hours of using Emacs.
> So, it is not reproducible reliably, unfortunately.
> Next time, I will leave the gdb session running, so that I can check the
> state in more details if necessary.

Thanks.  The commands below should be a starting point:

  (gdb) fr 10

Make sure frame #10 is indeed in plist_get, and adjust the frame
number if not.

  (gdb) p tail
  (gdb) xtype
  (gdb) p prop
  (gdb) xtype
  (gdb) xsymbol

Finally, for the brave:

  (gdb) pp tail