(In reply to Michel Dänzer from comment #25)
> (In reply to Alan W. Irwin from comment #24)
> > Just now the direct X server failed with a segfault (see the attached log
> > file for the details).
> 
> Looks like a Mesa bug. Please install the libgl1-mesa-dri-dbgsym package and
> attach another log file if it happens again.

Good idea, but I cannot follow up on it.
Debian Jessie = oldstable had debug packages for libgl1-mesa-dri, but I
can find nothing equivalent for Debian Stretch (not relevant to my Debian
Buster box but I looked for it nevertheless) or Debian Buster.  Debian Sid has
such packages, but they are all for non-official hardware platforms and not for
my AMD64 hardware platform.

Is there any further follow up you can recommend for the NMI-related error
messages for the latest kernel lockup?