Application that crashed: kontact
Version of the application: 4.3.1
KDE Version: 4.3.1 (KDE 4.3.1)
Qt Version: 4.5.2
Operating System: Linux 2.6.30.8-64.fc11.x86_64 x86_64
Distribution: "Fedora release 11 (Leonidas)"

What I was doing when the application crashed:
I close Kontact and try to restart it whitout waiting too long. (1-2 seconds).
Kontact ends up with a segmentation fault.

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f9a737dd820 (LWP 7115))]

Thread 2 (Thread 0x7f9a54d50910 (LWP 7225)):
#0  0x00000033ea60b2f9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x0000003728e5adfb in QWaitConditionPrivate::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#3  0x0000003729c818e4 in QHostInfoAgent::run (this=0x3531340) at kernel/qhostinfo.cpp:260
#4  0x0000003728e59d45 in QThreadPrivate::start (arg=0x3531340) at thread/qthread_unix.cpp:188
#5  0x00000033ea60686a in start_thread () from /lib64/libpthread.so.0
#6  0x00000033e9ade3bd in clone () from /lib64/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f9a737dd820 (LWP 7115)):
[KCrash Handler]
#5  bm_find (cs=<value optimized out>, skiptable=<value optimized out>, pl=<value optimized out>, puc=<value optimized out>, index=<value optimized out>, l=<value optimized out>, 
    uc=<value optimized out>) at tools/qstringmatcher.cpp:77
#6  qFindStringBoyerMoore (cs=<value optimized out>, skiptable=<value optimized out>, pl=<value optimized out>, puc=<value optimized out>, index=<value optimized out>, l=<value optimized out>, 
    uc=<value optimized out>) at tools/qstringmatcher.cpp:320
#7  0x00007f9a74e5dfe6 in Kontact::MainWindow::activatePluginModule() () from /usr/lib64/libkontactprivate.so.4
#8  0x0000000000404542 in _start ()

Reported using DrKonqi