After approximately a few weeks ago, I've been experiencing one of the
strangest issues since using openSUSE: While watching certain videos on Youtube
under Firefox, there is a probability that the operating system will crash.
This only seems to happen while watching certain videos... I can play some
clips as much as I want and nothing happens, but if I play others the OS may
crash typically somewhere between 2 and 10 minutes. What's stranger is that
there's a completely different effect every time, and there is no single
crash... the list of possible outcomes I've experienced so far includes:

- The computer simply freezes: I can no longer move the mouse cursor, use any
keys (including toggling the NumLock / CapsLock leds), etc. Strangely enough,
the audio of the video continues to play, even if the image is frozen.

- The machine reboots by itself. The screen suddenly goes black for a few
seconds, then I seamlessly find myself at the BIOS startup screen. The power
LED stays up and I don't hear the typical "click" sound which normally occurs
when you power off a computer... it acts as if software triggered.

- I am logged out and immediately find myself in the login manager. It's
exactly as if I clicked the "log out" button, except I don't press any keys nor
have any applications that could automatically issue this command.

- The Firefox process freezes, but with a bizarre side effect: Any process that
tries to kill or create a new process from there on will itself freeze
immediately! For example: If I open Konsole and type in "dolphin" to open the
file manager, the cursor goes one line down and stays there... same thing if I
try to kill a process with the kill command. If I try to start up a program
from the kickoff launcher, plasmashell will freeze. If I try to launch
something from krunner, krunner will freeze. I even logged off my normal user
account, pressed control + alt + f1 to start a new runlevel, logged in as root,
and tried to kill or start processes there... same thing.

- In the best case scenario, Firefox simply crashes and I can start it back up
again.

Note: I do not believe this to be caused by faulty hardware. I use many
programs on this machine, including hardware intensive games... I do not
experience such crashes with anything else. Also I've recently changed video
cards, and moved from the r600 driver to radeonsi... I remember that the issue
used to happen on the old one as well, although I think it stopped at some
point, possible after a certain package update. I don't use the proprietary
video driver, and am running openSUSE Tumbleweed.