[OpenJDK 2D-Dev] Defect 7032904(XRender: Java2Demo) remains

[Andrew Hughes]

----- Original Message -----
> Hi Frank,
> 
> >   Recently our team discovered defect 7032904(XRender: Java2Demo : Infinite
> > loop in Java_sun_java2d_loops_MaskBlit_MaskBlit on OEL 5.6 x64) still
> > exists
> > in latest JDK (7u21) on SLES10SP4.  It can be easily reproduced by running
> > SwingSet2 with Nimbus LAF.  The issue is also seen in Java 8.  Can anybody
> > look into it?
> 
> Thanks for reporting the issue, I'll have a look at it. Most likely
> the code which is detecting the libXrender package-info version
> doesn't find the package-info files at the expected place and
> conservatively keeps the xrender pipeline enabled.
> 
> The root problem still remains, we can not reliably detect the version
> of libXrender library used without targeting and testing every
> possibly affected distribution separately.
> As the versions of kernel and libXrender usually stay quite coherent
> for problematic distributions (old kernel == affected libXrender) and
> it is very easy to query the version of the linux-kernel currently
> running, I would propose to further restrict use of the xrender
> pipeline to systems running >= Linux-2.6.32, which is currently the
> oldest LTS kernel still supported. 2.6.32 was released in Dec. 2009.
> Hopefully this will not only avoid running into the libXrender-bug,
> but also avoid many driver-bugs caused by old and outdated drivers for
> the local use-case. In case of false positives it reverts back to the
> X11 backend instead, which in my opinion is the right thing to do in
> the event of uncertainty.
> 

Do you know which versions of libXrender are supported?  We can check the version
at configure time:

$ pkg-config --modversion renderproto
0.11.1

and disable the extension at compile-time.  This is especially true with 6 where,
IIRC, it's a patched-in option which is enabled by default, not part of upstream
OpenJDK.

Basing it on kernel version seems very dodgy to me.  I change my kernel version all
the time and it's completely unrelated to the version of Xrender I'm running.

> Regards, Clemens
> 
> PS: RHEL 5.5/5.6 runs linux-2.6.18
> SLES-10 runs linux-2.6.16.
> 
> Ubuntu 10.04 LTS (and higher) and Debian squeeze (6.0) both use
> Linux-2.6.32 and therefore would be supported.
> 

-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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