compiz crashed with SIGSEGV in CompScreen::insertServerWindow()

[skipper]

I was browsing the running applications by Alt-Tab, then the whole desktop got frozen, then few seconds later compiz restarted.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: unity 4.16.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-11.18-generic 3.0.4
Uname: Linux 3.0.0-11-generic i686
ApportVersion: 1.23-0ubuntu1
Architecture: i386
Date: Fri Sep 23 21:10:49 2011
ExecutablePath: /usr/bin/compiz
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta i386 (20110920.1)
ProcCmdline: compiz
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x806d081 <_ZN10CompScreen18insertServerWindowEP10CompWindowm+193>: mov 0xc(%eax),%eax
 PC (0x0806d081) ok
 source "0xc(%eax)" (0x0000000c) not located in a known VMA region (needed readable region)!
 destination "%eax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity
StacktraceTop:
 CompScreen::insertServerWindow(CompWindow*, unsigned long) ()
 PrivateWindow::reconfigureXWindow(unsigned int, XWindowChanges*) ()
 CompWindow::configureXWindow(unsigned int, XWindowChanges*) ()
 CompWindow::raise() ()
 PluginAdapter::FocusWindowGroup(std::vector<unsigned long, std::allocator<unsigned long> >) () from /usr/lib/compiz/libunityshell.so
Title: compiz crashed with SIGSEGV in CompScreen::insertServerWindow()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[Apport retracing service (apport)]

StacktraceTop:
 CompScreen::insertServerWindow (this=0xa068d58, w=0xaebfff00, aboveId=18999661) at /build/buildd/compiz-0.9.5.94+bzr20110919/src/screen.cpp:2672
 PrivateWindow::reconfigureXWindow (this=0xb4100858, valueMask=96, xwc=0xbfb6f5b4) at /build/buildd/compiz-0.9.5.94+bzr20110919/src/window.cpp:2740
 CompWindow::configureXWindow (this=0xaedd3270, valueMask=96, xwc=0xbfb6f5b4) at /build/buildd/compiz-0.9.5.94+bzr20110919/src/window.cpp:2967
 CompWindow::raise (this=0xaedd3270) at /build/buildd/compiz-0.9.5.94+bzr20110919/src/window.cpp:3482
 PluginAdapter::FocusWindowGroup (this=0xa52fdc8, window_ids=...) at /build/buildd/unity-4.16.0/plugins/unityshell/src/PluginAdapter.cpp:567

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[David Barth (dbarth)]

There are occurences of the bug with a version as recent as 4.18.0 AFAICT.

@Jason: with your knowledge of the switcher code, could you determine the circumstances that crash is ocurring in? I imagine it is about to display a thumbnails or switch to an application and something funny is happening with a window related to that application and it goes into the wrong code path in insertServerWindow().

[Alistair Buxton (a-j-buxton)]

I got this crash when I tried to move a gimp toolbox window with alt-drag.