unity-2d-launcher crashed in kvm/cirrus

Binary package hint: unity-2d

When trying to start a unity 2d session, the session crashes and the login screen appears again.
Running unity-2d-launcher in a recovery session shows a segfault while drawing the launcher, see the attached backtrace.

The numbers in the qt_memfill32_sse2 call (frame 0) suggest a 32 bpp image is being copied in a 24 bpp pixmap.
Frame 1 shows we are drawing something with width=66, height=736, that's 48576 pixels, which matches count in the memfill call in frame 0. Memfill uses 4 bytes per pixel and would need 194304 bytes but the destination only has room for 147456 bytes, which matches 3 bytes per pixel:
/proc/4924/maps:7fffd9df1000-7fffd9e15000 rw-s 00000000 00:04 3178496 /SYSV00000000 (deleted)
(compare the addresses with dest and dst128 in frame 0)

Reverting bzr commit 468 "Do not call QApplication::setColorSpec" solves this issue. With the commit reverted the unity 2d session starts correctly and all icons and windows look fine.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: unity-2d-launcher 3.8.6-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.39-3.10-generic 2.6.39
Uname: Linux 2.6.39-3-generic x86_64
Architecture: amd64
Date: Sun May 29 17:08:59 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: unity-2d
UpgradeStatus: Upgraded to oneiric on 2011-05-28 (1 days ago)