Quick heads-up: Ubuntu memory leak issue

[Adam Williamson]

Hey everyone, just a quick heads-up. Some of you may have read about a
memory leak that cropped up very late in Ubuntu 10.04 development
process. They kindly put this phrase in their explanation of the bug:

"One possible solution is to roll back the GLX 1.4 enablement patches,
and the patch which caused the memory leak to appear. These GLX patches
were produced by RedHat and incorporated into Debian, they were not
brought in due to Ubuntu-specific requirements"

which can obviously create the impression that the patches in question
actually come from Red Hat Enterprise Linux, or from Fedora.

Short story for the impatient: the problematic patch is not in any
version of Fedora and never has been, Fedora is not subject to this
memory leak and never has been.

So if you see any stories drawing the implication that Fedora is also
subject to this leak, please feel free to correct them - it isn't.

Longer version for the curious: I'm not sure about the claim that the
'GLX 1.4 enablement patches' come from Red Hat, they may be in RHEL for
some reason, but they're not in Fedora; we wouldn't need to backport GLX
1.4 from X server 1.8 to 1.7 as we're just shipping X server 1.8 in
Fedora 13 anyway.

Regardless, the actual patch that caused the problem in Ubuntu was not
part of the GLX 1.4 backport, but was an attempt to fix this bug:

https://bugs.freedesktop.org/show_bug.cgi?id=26394

Sometimes X would crash when Clutter-based apps closed. Fedora did
actually suffer from this bug too:

https://bugzilla.redhat.com/show_bug.cgi?id=579756

However, Ubuntu and Fedora took different approaches to fixing it.
Ubuntu seems to have jumped on one of Jesse Barnes' early attempts to
fix the problem (Jesse works for RH, hence the Red Hat link). In the
end, though, if you read the upstream bug, Jesse ceded to Kristian
Høgsberg (who, for the record, works for Intel), who provided a better
fix which was committed to upstream. For Fedora 13, we took Kristian's
fix, not any of Jesse's attempts. This was included in
xorg-x11-server-1.8.0-7.fc13 . That seems to have caused a couple of
problems with compositing managers:

https://bugzilla.redhat.com/show_bug.cgi?id=584832
https://bugzilla.redhat.com/show_bug.cgi?id=577142

-7 was sent as a candidate update for F13, got bad Bodhi feedback (as
you'd expect) and was withdrawn; it never went into the 'stable' F13
repo (the one from which the final F13 will actually be built). The bugs
were fixed by adding one more upstream patch, from Michel Dänzer:

http://cvs.fedoraproject.org/viewvc/rpms/xorg-x11-server/F-13/xserver-1.8.0-dri2-fix-handling-of-redirected-pixmaps.patch?view=markup

to xorg-x11-server-1.8.0-8.fc13 . That build has good feedback:

https://admin.fedoraproject.org/updates/xorg-x11-server-1.8.0-8.fc13

and was pushed to F13 updates two days ago. So in summary our processes
worked very well, we didn't jump on an incomplete fix, we didn't push
the initial upstream fix to the 'stable' F13 because our feedback system
made us aware of the problems it caused, we did push the fully-working
fixed package when it was confirmed ready, and we were never at any
point subject to the memory leak issue. This is actually quite a nice
story of our QA processes working effectively, if someone's looking for
such a thing. =)
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Fedora Talk: adamwill AT fedoraproject DOT org
http://www.happyassassin.net