This information is from the site i learned about the solution for this issue
( Couldn't open libGL.so.1: /usr/lib/x86_64-linux-gnu/libGL.so.1: undefined symbol: _glapi_tls_Current )
Package: libgl1-mesa-glx
Version: 13.0.6-1+b2
Severity: serious

Dear maintainers,

thanks for your work with the X stack, it's really appreciated :-)

I had today a very disapointing experience with Debian.
I did the daily aptitude update && aptitude upgrade of testing buster
in a laptop (XFCE) to find that the system would show no graphical interface
no longer. In fact, the behaviour is a complete freeze of the machine.

This is what I did to point to libgl1-mesa-glx as the main problem.

1) I upgraded a bunch of packages, usual daily update:

--- 8< ---
Aptitude 0.8.9: log report
Tue, Oct 17 2017 19:26:20 +0200

IMPORTANT: this log only lists intended actions; actions which fail
due to dpkg problems may not be completed.

Will install 50 packages, and remove 1 packages.
27.1 MB of disk space will be used

[REMOVE, NOT USED] libllvm3.9:amd64 1:3.9.1-10
[INSTALL, DEPENDENCIES] libegl-mesa0:amd64 17.2.2-1
[INSTALL, DEPENDENCIES] libegl1:amd64 0.2.999+git20170802-5
[INSTALL, DEPENDENCIES] libgl1:amd64 0.2.999+git20170802-5
[INSTALL, DEPENDENCIES] libgles2:amd64 0.2.999+git20170802-5
[INSTALL, DEPENDENCIES] libglvnd0-nvidia:amd64 375.82-5
[INSTALL, DEPENDENCIES] libglx-mesa0:amd64 17.2.2-1
[INSTALL, DEPENDENCIES] libglx0:amd64 0.2.999+git20170802-5
[INSTALL, DEPENDENCIES] libllvm5.0:amd64 1:5.0~+rc2-1
[UPGRADE] dirmngr:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gir1.2-soup-2.4:amd64 2.60.0-1 -> 2.60.1-1
[UPGRADE] gnupg:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gnupg-l10n:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gnupg-utils:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gpg:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gpg-agent:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gpg-wks-client:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gpg-wks-server:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gpgconf:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gpgsm:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] gpgv:amd64 2.2.1-1 -> 2.2.1-2
[UPGRADE] libcap2:amd64 1:2.25-1 -> 1:2.25-1.1
[UPGRADE] libcap2-bin:amd64 1:2.25-1 -> 1:2.25-1.1
[UPGRADE] libegl1-mesa:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] libgbm1:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] libgl1-mesa-dri:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] libgl1-mesa-glx:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] libglapi-mesa:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] libgles2-mesa:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] libinput-bin:amd64 1.8.2-1 -> 1.8.3-1
[UPGRADE] libinput10:amd64 1.8.2-1 -> 1.8.3-1
[UPGRADE] libpam-cap:amd64 1:2.25-1 -> 1:2.25-1.1
[UPGRADE] libpam-systemd:amd64 234-3 -> 235-2
[UPGRADE] libparted-fs-resize0:amd64 3.2-17 -> 3.2-18
[UPGRADE] libparted2:amd64 3.2-17 -> 3.2-18
[UPGRADE] libsoup-gnome2.4-1:amd64 2.60.0-1 -> 2.60.1-1
[UPGRADE] libsoup2.4-1:amd64 2.60.0-1 -> 2.60.1-1
[UPGRADE] libsystemd0:amd64 234-3 -> 235-2
[UPGRADE] libtag1v5:amd64 1.11.1+dfsg.1-0.1 -> 1.11.1+dfsg.1-0.2
[UPGRADE] libtag1v5-vanilla:amd64 1.11.1+dfsg.1-0.1 -> 1.11.1+dfsg.1-0.2
[UPGRADE] libtagc0:amd64 1.11.1+dfsg.1-0.1 -> 1.11.1+dfsg.1-0.2
[UPGRADE] libudev1:amd64 234-3 -> 235-2
[UPGRADE] libwayland-egl1-mesa:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] libxatracker2:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] mesa-va-drivers:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] mesa-vdpau-drivers:amd64 13.0.6-1+b2 -> 17.2.2-1
[UPGRADE] parted:amd64 3.2-17 -> 3.2-18
[UPGRADE] shared-mime-info:amd64 1.8-1 -> 1.9-2
[UPGRADE] systemd:amd64 234-3 -> 235-2
[UPGRADE] systemd-sysv:amd64 234-3 -> 235-2
[UPGRADE] udev:amd64 234-3 -> 235-2

Log complete.
--- 8< ---

2) The system freezes.

After inspecting logs, reinstalling random packages, restarting ligthdm, trying
with gdm3, blaming radeon drivers, blaming debian for not having a proper apt
rollback facility, blaming all the god of the seven kingdoms, I found this
line in '/var/log/lightdm/x-1.log':

--- 8< ---
[...]
Couldn't open libGL.so.1: /usr/lib/x86_64-linux-gnu/libGL.so.1: undefined symbol: _glapi_tls_Current
[...]
--- 8< ---

3) I downgraded libgl1-mesa-glx, like this:

--- 8< ---

Aptitude 0.8.9: log report
Tue, Oct 17 2017 23:49:29 +0200

IMPORTANT: this log only lists intended actions; actions which fail
due to dpkg problems may not be completed.

Will install 2 packages, and remove 3 packages.
831 kB of disk space will be freed

[REMOVE, NOT USED] libglx0:amd64 0.2.999+git20170802-5
[REMOVE, DEPENDENCIES] libglx-mesa0:amd64 17.2.2-1
[DOWNGRADE] libgl1-mesa-glx:amd64 17.2.2-1 -> 13.0.6-1+b2
[DOWNGRADE] libglapi-mesa:amd64 17.2.2-1 -> 13.0.6-1+b2
[REMOVE (PURGE)] libgl1:amd64 0.2.999+git20170802-5

--- 8< ---

And then the system started working again.

So, it seems like the undefined symbol thing is really important and the
laptop freezes due to this.

At first I blamed libgl1, but I'm not sure if how much they are related.

4) Probably unrelated to this bug, I could send this to debian-devel if you
agree:

In a common laptop, an user would use the graphical environment to configure
the network. If the graphical environment is not available, the network won't be
available either. This means that fixing this issue is impossible for a common
user. It took me (a DD) a couple of hours to deal with this.
So, I get 2 conclusions:

a) we (Debian) perhaps need some mechanisms to rollback aptitude upgrades
automagically (i.e: rollback last upgrade)

b) we (Debian) perhaps need an extensive guide to troubleshoot graphical
environments problems, which may lead to chicken-eggs issues hard to deal.