Dear Maintainer,

(This is my first Debian bug report, so apologies if I make any mistakes)

Recently, I performed a "cautious upgrade" of my system using Muon package manager. This affected a number of packages, including libgl1-mesa-dri.
After this, I found that my system would freeze when booting into X and/or SDDM, just displaying a white underscore on a black screen,
and not even permitting switching terminal with ctrl-alt-F*.

I remoted into my system, and downgraded the various packages affected, using .deb files downloaded from snapshot.debian.org, in order
to get my computer usable again. After doing this, X could boot again. I experimented with upgrading and downgrading various packages in order
to reproduce the issue; it seems that the faulty package is libgl1-mesa-dri, of which I have both :amd64 and :i386 installed, and they both depend
on each other so I can't test them individually.

With these packages at version 19.1.6-1, the X server crashes with a SIGSEGV every time; at 18.3.6-2, they work fine, so presumably the issue
is in a version between these two, althoug these are the only ones I've tried. The stacktrace from X should be attached below; I didn't see anything
paticuarly interesting in dmesg, and I'm not sure if Mesa keeps it's own log files anywhere so I've not been able to check them.

I'm happy to provide more information if required; I have basic knowledge with debugging software, although I'd need a bit of guidance about where
to start.

Thanks,
Jim Joyce

/usr/local/lib/x86_64-linux-gnu/dri/radeonsi_dri.so presumably isn't
from a Debian package, does moving that away help?

This can't do any good on a system with a Radeon (installing nvidia):

Start-Date: 2019-09-25  19:28:47
Commandline: apt --fix-broken install
Requested-By: jimj316 (1000)
Install: libgles1:i386 (1.1.0-1+b1, automatic), libgles2:i386
(1.1.0-1+b1, automatic), glx-alternative-nvidia:amd64 (1.0.0,
automatic), nvidia-alternative:amd64 (430.50-1, automatic)
Upgrade: libnvidia-glvkspirv:amd64 (418.88-1, 430.50-1),
libnvidia-glvkspirv:i386 (418.88-1, 430.50-1), libgles-nvidia1:i386
(418.88-1, 430.50-1), libgles-nvidia2:i386 (418.88-1, 430.50-1),
nvidia-vulkan-icd:amd64 (418.88-1, 430.50-1), nvidia-vulkan-icd:i386
(418.88-1, 430.50-1), nvidia-egl-icd:i386 (418.88-1, 430.50-1),
libgl1-nvidia-glvnd-glx:i386 (418.88-1, 430.50-1), libglx-nvidia0:amd64
(418.88-1, 430.50-1), libglx-nvidia0:i386 (418.88-1, 430.50-1),
libegl-nvidia0:amd64 (418.88-1, 430.50-1), libegl-nvidia0:i386
(418.88-1, 430.50-1), nvidia-driver-libs:i386 (418.88-1, 430.50-1),
libnvidia-glcore:amd64 (418.88-1, 430.50-1), libnvidia-glcore:i386
(418.88-1, 430.50-1), libnvidia-eglcore:amd64 (418.88-1, 430.50-1),
libnvidia-eglcore:i386 (418.88-1, 430.50-1)
End-Date: 2019-09-25  19:29:56

though you had glx-diversions already installed before this meaning you
probably had amdgpu-pro installed, and we don't support that.