Recent libX11 update broke emacs

[Kevin Oberman]

Yes, that fixes the problem. All looks good.

Thanks for the quick fix to both you and Ashish!
--
Kevin Oberman, Part time kid herder and retired Network Engineer
E-mail: rkoberman at gmail.com
PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683


On Tue, Aug 4, 2020 at 2:06 AM Niclas Zeising <zeising+freebsd at daemonic.se>
wrote:

> On 2020-08-04 06:48, Ashish SHUKLA wrote:
> > On 8/4/20 10:04 AM, Ashish SHUKLA wrote:
> >> On 8/4/20 3:38 AM, Niclas Zeising wrote:
> >>> On 2020-08-03 19:07, Kevin Oberman wrote:
> >>>> This is a weird problem and I'm uncertain if it is in libW11,
> > x11-server,
> >>>> or emacs. As a result, I'm crossposting to both lists.
> >>>>
> >>>> Yesterday, after upgrading libX11 and x11-server, I could no longer
> run
> >>>> Emacs to an  X display. It crashed quickly with a segmentation error
> >>>> in the
> >>>> pthread library. Oddly, I could run it to my local xserver from a
> remote
> >>>> system.
> >>>
> >>> Where does the segfault occur before entering pthreads?
> >>>
> >>>> Rolling back the x11 server did not help nor did rolling back libX11
> or
> >>>> even both of them. I had to roll back libX11 first and build the
> server
> >>>> with the old libX11. Rebuilding emacs with the new ports made no
> >>>> difference.
> >>>
> >>> Which version of the server did you build?  The patch to xorg-server is
> >>> trivial, just switching out malloc for calloc have the memory 0
> >>> initialized.  The patch to libX11 is rather more involved.
> >>> It is possible that someone accidentally changed the ABI of libX11, I
> >>> guess.  What happens if you use the version with just the security
> fixes
> >>> (the version I committed first, and that was merged to the Q3 branch.)
> >>>
> >>>>
> >>>> Since the old libX11 contains a very serious vulnerability, I  really
> >>>> hate
> >>>> to leave it this way, but I also have a hard time getting anything
> done
> >>>> without emacs. Nothing other than emacs seems to have a problem with
> > this
> >>>
> >>> There is one commit after libX11 1.6.10, that takes care of a
> regression.
> >>> Can you apply
> >>>
> >
> https://gitlab.freedesktop.org/xorg/lib/libx11/-/commit/93fce3f4e79cbc737d6468a4f68ba3de1b83953b
> >>> on top of the libX11 1.6.10 update and see if that fixes anything?
> >>>
> >>> Regards
> >>
> >> Able to get Emacs to segfault:
> >>
> >> λ lldb -e /usr/local/bin/emacs
> >> (lldb) target create "/usr/local/bin/emacs"
> >> Current executable set to '/usr/local/bin/emacs' (x86_64).
> >> (lldb) run -Q
> >> Process 36196 launching
> >> Process 36196 launched: '/usr/local/bin/emacs' (x86_64)
> >> Process 36196 stopped
> >> * thread #1, name = 'emacs-28.0.50', stop reason = signal SIGSEGV:
> >> invalid address (fault address: 0x0)
> >>      frame #0: 0x0000000000427ca0
> >> emacs`best_xim_style(xim=0x0000000000000000) at xfns.c:2629:21
> >> (lldb) bt
> > [...]
> >
> >>
> >>
> >> And workaround is launching Emacs like: env -u XMODIFIERS emacs
> >>
> >> I'll try the libX11 patch and give it a shot.
> >
> > Emacs, with libX11 built with the patch, works fine now. It seems like
> > it's also reported in Debian[1], and they merged it. Maybe we can do the
> > same ?
> >
> > References:
> > [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=966691
> >
>
> Thank you, I'll see about adding that patch to the port and package then.
> It looks like this is both a bug in libX11 and to some extent also emacs?
>
> Kevin, can you double check that the patch works for you.  I find it
> strange that you have to rebuild both xorg-server and libX11 for it to
> work, are you forcing static linkage somewhere?
> Regards
> --
> Niclas
>