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: Tue, 23 Mar 2021 10:18:25 -0400
> 
> >   break buffer.c:1840 if redisplaying_p != 0 && b->window_count > 0
> 
> This triggered today.
> 
> #0  0x00005555555e1b6d in redisplay_internal ()
>     at ../../master/src/xdisp.c:15789

I don't understand: the breakpoint was supposed to be on line 1840 in
buffer.c, so why does frame #0 show line 15789 in xdisp.c?  What am I
missing here?  Is this the right backtrace?