[CentOS] A bit more on the Firefox 3.5.issue

Tue Aug 11 05:33:41 UTC 2009
Mike A. Harris <mharris at mharris.ca>

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Ron Blizzard wrote:
> I set up a CentOS desktop computer for my brother and his kids. When
> Firefox 3.5 came out he decided to download and install it like he
> would Windows (he doesn't yet understand the repository system). He's
> been telling me that it works fine, even though I was skeptical due to
> my experience with Firefox 3.5 on CentOS 5.3. Then today, he says,
> "Oh, by the way, the CentOS computer has been rebooting itself every
> now and then." What?! (This is where he is in Linux -- doesn't realize
> that it's not like Windows, that it's not supposed to reboot
> randomly.) "Does it do it when you're in Firefox?" "Yes."
> 
> He's okay, though, just a matter of uninstalling his home root version
> of Firefox -- I've been updating his computer with yum, so he still
> has the newest *repository* release of Firefox also.
> 
> At any rate, just to let everyone know, whatever the issue is with
> Firefox 3.5 and *some* CentOS 5.3 computers (an Xorg graphics card
> incompatibility issue?) -- it goes beyond the RPM package released by
> Michael Harris. As for myself, I'm just going to wait for the
> repository Firefox 3.5 upgrade.

If you run any unprivileged userland software, which includes most
software on the system including firefox, and your computer reboots,
then you either have broken video drivers, a buggy kernel (possibly
DRM), or if you're using 3rd party video drivers or other 3rd party
kernel modules, they are likely culprits as well.  Alternatively it
could be system overheating (unlikely for the firefox triggered issue
described), hardware incompatibility, or some other hardware issue,
possibly even a bad BIOS or something.

Unpriviledged userland applications like firefox do not have any rights
whatsoever to execute anything that can directly crash the computer.  As
such, if anyone ever runs firefox or any other userland application, and
their computer reboots or crashes, forget about the application that you
ran that appears to have triggered something, and look in
/var/log/messages and /var/log/Xorg*.log looking for clues as to what
might have failed.  In many cases you will not find any evidence left
behind in the logs from the failures, and must resort to other forms of
troubleshooting.

Quite often, the culprit is the video driver, either the Xorg driver,
the 3D driver, or the kernel portion (DRM, or equivalent proprietary
alternative), and so that's where I'd start looking.  Disable 3D
acceleration in your xorg.conf, try again.  Disable 2D acceleration if
need be.  Experiment with other video driver options (read the docs for
the driver you're using), etc.

Now, someone might say "yes, but firefox 3 doesn't reboot the computer,
but 3.5 does, so it must be firefox".  Which of course is flawed logic,
because we already know unprivileged userland code such as firefox does
not have permission to access anything that can directly lock up the
hardware or reboot the computer.  If someone is having this problem, the
obvious cause is that firefox 3.5 most likely has new functionality that
does not exist in firefox 3, which triggers a video driver bug that
older firefox didn't trigger because it didn't try to use the video
driver in that manner.

I'm focusing on the video driver being the problem because that is the
case 99.9% of the time, however if you try the troubleshooting I suggest
above and can't narrow the problem down, you might need to try using
another video driver (nouveau, radeon, radeonhd, vesa, etc.) - just to
see if it makes any difference.  If you use a different driver and the
problem goes away, then you can most likely conclude the video driver is
buggy.  Another possibility is triggering an X server bug, but that's
less likely.

Anyway, I hope this helps narrow down the true problem for anyone
experiencing this.  Look for the problem, not the trigger (firefox).

Hope this helps.



- --
Mike A. Harris
http://mharris.ca  |  https://twitter.com/mikeaharris

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