compiz crashed with SIGSEGV in unity::switcher::SwitcherController::CompareSwitcherItemsPriority()

[Harrison Neal]

NOTE: I *DON'T* believe this is related to #916879 - #916879 refers to a segfault at 0x0, whereas this one refers to a non-zero address.

After login, I launched several applications from the launcher/dock at once and began using Ctrl+Alt+Shift+ArrowKey to organize programs into different workspaces as the various windows appeared. Before the last program finished opening, I tried to use Alt+Tab, the screen seized up, the unity interface disappeared and came back.

ProblemType: Crash
DistroRelease: Ubuntu 11.10
Package: unity 4.28.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-16.28-generic 3.0.17
Uname: Linux 3.0.0-16-generic x86_64
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Tue Feb 21 15:47:35 2012
ExecutablePath: /usr/bin/compiz
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
ProcCmdline: compiz
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7f0473bd2565 <_ZN5unity8switcher18SwitcherController28CompareSwitcherItemsPriorityEP20AbstractLauncherIconS3_+37>: mov 0x0(%rbp),%rax
 PC (0x7f0473bd2565) ok
 source "0x0(%rbp)" (0x00000080) not located in a known VMA region (needed readable region)!
 destination "%rax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity
StacktraceTop:
 unity::switcher::SwitcherController::CompareSwitcherItemsPriority(AbstractLauncherIcon*, AbstractLauncherIcon*) () from /usr/lib/compiz/libunityshell.so
 void std::__insertion_sort<__gnu_cxx::__normal_iterator<AbstractLauncherIcon**, std::vector<AbstractLauncherIcon*, std::allocator<AbstractLauncherIcon*> > >, bool (*)(AbstractLauncherIcon*, AbstractLauncherIcon*)>(__gnu_cxx::__normal_iterator<AbstractLauncherIcon**, std::vector<AbstractLauncherIcon*, std::allocator<AbstractLauncherIcon*> > >, __gnu_cxx::__normal_iterator<AbstractLauncherIcon**, std::vector<AbstractLauncherIcon*, std::allocator<AbstractLauncherIcon*> > >, bool (*)(AbstractLauncherIcon*, AbstractLauncherIcon*)) () from /usr/lib/compiz/libunityshell.so
 unity::switcher::SwitcherController::Show(unity::switcher::SwitcherController::ShowMode, unity::switcher::SwitcherController::SortMode, bool, std::vector<AbstractLauncherIcon*, std::allocator<AbstractLauncherIcon*> >) () from /usr/lib/compiz/libunityshell.so
 UnityScreen::altTabInitiateCommon(CompAction*, unsigned int, std::vector<CompOption, std::allocator<CompOption> >&) () from /usr/lib/compiz/libunityshell.so
 UnityScreen::altTabForwardInitiate(CompAction*, unsigned int, std::vector<CompOption, std::allocator<CompOption> >&) () from /usr/lib/compiz/libunityshell.so
Title: compiz crashed with SIGSEGV in unity::switcher::SwitcherController::CompareSwitcherItemsPriority()
UpgradeStatus: Upgraded to oneiric on 2011-10-15 (129 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare vboxusers

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #931163, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.