bug#47244: 28.0.50; SIGSEGV in long-runnning Emacs

[Eli Zaretskii]

> From: Michael Welsh Duggan <mwd@cert.org>
> Cc: "mwd@md5i.com" <mwd@md5i.com>,
>         "schwab@linux-m68k.org"
>  <schwab@linux-m68k.org>,
>         "47244@debbugs.gnu.org" <47244@debbugs.gnu.org>
> Date: Mon, 29 Mar 2021 11:21:05 -0400
> 
> 2) From the *Group* buffer I hit `C-g` to cancel its attempt, and `^` to
>    switch to the Gnus *Sever* buffer.
> 3) In that buffer I go to the imap connection and type `C O`, which runs
>    `gnus-server-close-server` and `gnus-server-open-server`,
>    respectively.
> 4) I type `q` to exit the server buffer.  This is when the breakpoint
>    triggers.

Breakpoint or segfault?

> `g` calls the following function:
> 
>     (defun gnus-server-exit ()
>       "Return to the group buffer."
>       (interactive nil gnus-server-mode)
>       (gnus-run-hooks 'gnus-server-exit-hook)
>       (gnus-kill-buffer (current-buffer))

What is current-buffer at this point?