Bug 121655

Confirmed, I also had such crashes (2-3 times in some weeks), using Kubuntu Breezy. No idea, what causes them though, and no Akregator symbol in the bt.

Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
`system-supplied DSO at 0xffffe000' has disappeared; keeping its symbols.
[Thread debugging using libthread_db enabled]
[New Thread -1243879744 (LWP 8004)]
[KCrash handler]
#6  0xb5f73520 in malloc_usable_size () from /lib/tls/i686/cmov/libc.so.6
#7  0xb5f73cd0 in malloc_trim () from /lib/tls/i686/cmov/libc.so.6
#8  0xb5f742ca in free () from /lib/tls/i686/cmov/libc.so.6
#9  0xb6123c71 in operator delete () from /usr/lib/libstdc++.so.6
#10 0xb6123ccc in operator delete[] () from /usr/lib/libstdc++.so.6
#11 0xb6888a01 in QGDict::~QGDict () from /usr/share/qt3/lib/libqt-mt.so.3
#12 0xb6580a00 in QAsciiDict<QMetaData const>::~QAsciiDict ()
   from /usr/share/qt3/lib/libqt-mt.so.3
#13 0xb6580aa4 in QMemberDict::~QMemberDict ()
   from /usr/share/qt3/lib/libqt-mt.so.3
#14 0xb657ee84 in QMetaObject::~QMetaObject ()
   from /usr/share/qt3/lib/libqt-mt.so.3
#15 0xb657edcd in QMetaObjectCleanUp::~QMetaObjectCleanUp ()
   from /usr/share/qt3/lib/libqt-mt.so.3
#16 0xb691de7e in QTextEdit::qt_static_property ()
   from /usr/share/qt3/lib/libqt-mt.so.3
#17 0xb5f3c854 in __cxa_finalize () from /lib/tls/i686/cmov/libc.so.6
#18 0xb64a4ca3 in ?? () from /usr/share/qt3/lib/libqt-mt.so.3
#19 0xb6a13fe0 in ?? () from /usr/share/qt3/lib/libqt-mt.so.3
#20 0xb6d7aa78 in ?? ()
#21 0xbf8100f8 in ?? ()
#22 0xb64a4c7a in ?? () from /usr/share/qt3/lib/libqt-mt.so.3
#23 0xbf810120 in ?? ()
#24 0xb6a06460 in ?? () from /usr/share/qt3/lib/libqt-mt.so.3
#25 0xbf810108 in ?? ()
#26 0xb693260b in _fini () from /usr/share/qt3/lib/libqt-mt.so.3
#27 0xb693260b in _fini () from /usr/share/qt3/lib/libqt-mt.so.3
#28 0xb7f098f4 in _dl_rtld_di_serinfo () from /lib/ld-linux.so.2
#29 0xb5f3c5e7 in exit () from /lib/tls/i686/cmov/libc.so.6
#30 0xb5f25eac in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6
#31 0x080514b1 in _start () at ../sysdeps/i386/elf/start.S:119

*** Bug 121474 has been marked as a duplicate of this bug. ***

it crashed again

Backtrace follows:

(no debugging symbols found)
Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread 905529024 (LWP 3871)]
[KCrash handler]
#6  0x37c826b0 in malloc_usable_size () from /lib/tls/i686/cmov/libc.so.6
#7  0x37c82d50 in malloc_usable_size () from /lib/tls/i686/cmov/libc.so.6
#8  0x37c8334a in free () from /lib/tls/i686/cmov/libc.so.6
#9  0x37d1f522 in _dl_close () from /lib/tls/i686/cmov/libc.so.6
#10 0x36471d5a in dlopen () from /lib/tls/i686/cmov/libdl.so.2
#11 0x37f35106 in _dl_rtld_di_serinfo () from /lib/ld-linux.so.2
#12 0x364722bb in dlerror () from /lib/tls/i686/cmov/libdl.so.2
#13 0x36471d8a in dlclose () from /lib/tls/i686/cmov/libdl.so.2
#14 0x373b36bf in QLibraryPrivate::freeLibrary () from /usr/lib/libqt-mt.so.3
#15 0x373d7c54 in QLibrary::unload () from /usr/lib/libqt-mt.so.3
#16 0x373d7e56 in QLibrary::~QLibrary () from /usr/lib/libqt-mt.so.3
#17 0x373b70c1 in QComLibrary::~QComLibrary () from /usr/lib/libqt-mt.so.3
#18 0x373d5910 in QDict<QLibrary>::deleteItem () from /usr/lib/libqt-mt.so.3
#19 0x373cca3f in QGDict::clear () from /usr/lib/libqt-mt.so.3
#20 0x373d4c75 in QDict<QLibrary>::clear () from /usr/lib/libqt-mt.so.3
#21 0x373d4ca7 in QDict<QLibrary>::~QDict () from /usr/lib/libqt-mt.so.3
#22 0x373d2ca7 in QGPluginManager::~QGPluginManager ()
   from /usr/lib/libqt-mt.so.3
#23 0x372e4a03 in QPluginManager<QInputContextFactoryInterface>::~QPluginManager () from /usr/lib/libqt-mt.so.3
#24 0x372e4a40 in QSingleCleanupHandler<QPluginManager<QInputContextFactoryInterface> >::~QSingleCleanupHandler () from /usr/lib/libqt-mt.so.3
#25 0x372e48ba in QInputContextFactory::keys () from /usr/lib/libqt-mt.so.3
#26 0x37c4b844 in __cxa_finalize () from /lib/tls/i686/cmov/libc.so.6
#27 0x36fe7b9f in ?? () from /usr/lib/libqt-mt.so.3
#28 0x3758dd40 in ?? () from /usr/lib/libqt-mt.so.3
#29 0x3757ffbc in ?? () from /usr/lib/libqt-mt.so.3
#30 0x3ff3c7c8 in ?? ()
#31 0x374a79a3 in _fini () from /usr/lib/libqt-mt.so.3
#32 0x374a79a3 in _fini () from /usr/lib/libqt-mt.so.3
#33 0x37f358f4 in _dl_rtld_di_serinfo () from /lib/ld-linux.so.2
#34 0x37c4b5d7 in exit () from /lib/tls/i686/cmov/libc.so.6
#35 0x37c34eac in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6
#36 0x08050031 in ?? ()

Backtrace follows:

(no debugging symbols found)
Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread 906233536 (LWP 16141)]
[KCrash handler]
#6  0x37d2e6b0 in malloc_usable_size () from /lib/tls/i686/cmov/libc.so.6
#7  0x37d2ed50 in malloc_usable_size () from /lib/tls/i686/cmov/libc.so.6
#8  0x37d2f34a in free () from /lib/tls/i686/cmov/libc.so.6
#9  0x371429b1 in QtFontStyle::~QtFontStyle () from /usr/lib/libqt-mt.so.3
#10 0x37142a33 in QtFontFoundry::~QtFontFoundry () from /usr/lib/libqt-mt.so.3
#11 0x37142ab9 in QtFontFamily::~QtFontFamily () from /usr/lib/libqt-mt.so.3
#12 0x37142b76 in QFontDatabasePrivate::~QFontDatabasePrivate ()
   from /usr/lib/libqt-mt.so.3
#13 0x371436f0 in QSingleCleanupHandler<QFontDatabasePrivate>::~QSingleCleanupHandler () from /usr/lib/libqt-mt.so.3
#14 0x371424de in QFontDatabase::pointSizes () from /usr/lib/libqt-mt.so.3
#15 0x37cf7844 in __cxa_finalize () from /lib/tls/i686/cmov/libc.so.6
#16 0x37093b9f in ?? () from /usr/lib/libqt-mt.so.3
#17 0x37639d40 in ?? () from /usr/lib/libqt-mt.so.3
#18 0x3762bfbc in ?? () from /usr/lib/libqt-mt.so.3
#19 0x3f9e89f8 in ?? ()
#20 0x375539a3 in _fini () from /usr/lib/libqt-mt.so.3
#21 0x375539a3 in _fini () from /usr/lib/libqt-mt.so.3
#22 0x37fe18f4 in _dl_rtld_di_serinfo () from /lib/ld-linux.so.2
#23 0x37cf75d7 in exit () from /lib/tls/i686/cmov/libc.so.6
#24 0x37ce0eac in __libc_start_main () from /lib/tls/i686/cmov/libc.so.6
#25 0x08050031 in ?? ()

Bt from 123441:

Using host libthread_db library "/lib/libthread_db.so.1". 
 `system-supplied DSO at 0xffffe000' has disappeared; keeping its symbols. 
 [Thread debugging using libthread_db enabled] 
 [New Thread -1230334288 (LWP 4500)] 
 [KCrash handler] 
 #6  0xffffe410 in __kernel_vsyscall () 
 #7  0x473ef651 in raise () from /lib/libc.so.6 
 #8  0x473f115c in abort () from /lib/libc.so.6 
 #9  0x4742235b in __fsetlocking () from /lib/libc.so.6 
 #10 0x4742bc99 in mallopt () from /lib/libc.so.6 
 #11 0x4742adbf in mallopt () from /lib/libc.so.6 
 #12 0x4742ab84 in mallopt () from /lib/libc.so.6 
 #13 0x474297c9 in free () from /lib/libc.so.6 
 #14 0x477bec93 in operator delete () 
    from /usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.6/libstdc++.so.5 
 #15 0x477becef in operator delete[] () 
    from /usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.6/libstdc++.so.5 
 #16 0xb6d72b2b in ~MemBlock (this=0x0) at kallocator.cpp:38 
 #17 0xb6cdbfb6 in ~KZoneAllocator (this=0xb6ddf660) at kallocator.cpp:79 
 #18 0xb6d3e952 in __tcf_38 () at kcompletion.cpp:883 
 #19 0x473f268c in __cxa_finalize () from /lib/libc.so.6 
 #20 0xb6c56820 in __do_global_dtors_aux () 
    from /usr/kde/3.5/lib/libkdecore.so.4 
 #21 0xb6db81e6 in _fini () from /usr/kde/3.5/lib/libkdecore.so.4 
 #22 0x46bf4be9 in _dl_fini () from /lib/ld-linux.so.2 
 #23 0x473f23d7 in exit () from /lib/libc.so.6 
 #24 0x473dc0e4 in __libc_start_main () from /lib/libc.so.6 
 #25 0x08051521 in _start () 

*** Bug 123441 has been marked as a duplicate of this bug. ***

I cleaned up some static QString object in RSS::FileRetriever (using a static QString* instead), which can cause crashes on shutdown according to David.
And I haven't had this crash for some time now. Maybe that fixed it, don't know for sure... 

Please report if you have this bug with SVN 3.5 branch >= 516072 or upcoming 3.5.2.

This should be fixed by now.