apt-get crashed with SIGSEGV in pkgPolicy::GetCandidateVer()

[Ademar Arvati Filho]

just started lubuntu and openned firefox.

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: apt 0.8.16~exp12ubuntu8
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic 3.2.14
Uname: Linux 3.2.0-23-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu4
Architecture: amd64
Date: Tue Apr 17 08:47:39 2012
ExecutablePath: /usr/bin/apt-get
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
ProcCmdline: apt-get check -f -qq
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
 SHELL=/bin/sh
SegvAnalysis:
 Segfault happened at: 0x7f3532474930 <_ZN9pkgPolicy15GetCandidateVerERKN8pkgCache11PkgIteratorE+384>: movswl (%rax,%rdx,2),%eax
 PC (0x7f3532474930) ok
 source "(%rax,%rdx,2)" (0x014fdf0a) not located in a known VMA region (needed readable region)!
 destination "%eax" ok
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: apt
StacktraceTop:
 pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const&) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
 pkgDepCache::Init(OpProgress*) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
 pkgCacheFile::BuildDepCache(OpProgress*) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
 pkgCacheFile::Open(OpProgress*, bool) () from /usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
 ?? ()
Title: apt-get crashed with SIGSEGV in pkgPolicy::GetCandidateVer()
UpgradeStatus: Upgraded to precise on 2012-04-03 (13 days ago)
UserGroups:

[Apport retracing service (apport)]

StacktraceTop:
 pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const&) () from /tmp/tmpgySOf3/usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
 pkgDepCache::Init(OpProgress*) () from /tmp/tmpgySOf3/usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
 pkgCacheFile::BuildDepCache(OpProgress*) () from /tmp/tmpgySOf3/usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
 pkgCacheFile::Open(OpProgress*, bool) () from /tmp/tmpgySOf3/usr/lib/x86_64-linux-gnu/libapt-pkg.so.4.12
 ?? ()