bug#31233: 26.1; Emacs terminated unexpectedly

[Eli Zaretskii]

> From: nljlistbox2@gmail.com (N. Jackson)
> Cc: 31233@debbugs.gnu.org
> Date: Sat, 21 Apr 2018 23:28:55 -0400
> 
> > Yes, see the node "Crashing" in the Emacs manual.
> 
> Thanks. (I had tried looking in etc/DEBUG and didn't find the
> information there.)

etc/DEBUG is for developers; the manual explains to users how to
report crashes.

>   emacs_backtrace at /data/projects/vc/emacs/git/emacs/src/sysdep.c:2410
>   terminate_due_to_signal at /data/projects/vc/emacs/git/emacs/src/emacs.c:388
>   deliver_fatal_signal at /data/projects/vc/emacs/git/emacs/src/sysdep.c:1774
>   deliver_thread_signal at /data/projects/vc/emacs/git/emacs/src/sysdep.c:1744
>   deliver_fatal_thread_signal at 
> /data/projects/vc/emacs/git/emacs/src/sysdep.c:1782
>   ?? ??:0
>   mem_find at /data/projects/vc/emacs/git/emacs/src/alloc.c:4209
>   mark_maybe_object at /data/projects/vc/emacs/git/emacs/src/alloc.c:4808 
> (discriminator 4)

Hmm... signal 7 is SIGBUS on your system, right?  So this sounds like
one of the pointers in the red-black tree is not aligned correctly.  I
think we will need to see which pointer is that and what's its
relation to the root of the tree and to mem_z sentinel node concocted
by mem_find.  You should be able to show these values when/if the
crash happens again.

Thanks.