Application: kmail (4.8.3)
KDE Platform Version: 4.8.3 (4.8.3)
Qt Version: 4.8.1
Operating System: Linux 3.2.0-26-generic i686
Distribution: Ubuntu 12.04 LTS

-- Information about the crash:
I have seen many bugs on here which look similar and may (or may not) be the same as this one, but there is one added little trigger which I have a feeling might help.  This only happens to me when kmail is opened for the *first* time each day, or after I have rebooted during the day.  Other sessions once the machine is switched on and kmail is accessed for the first time, function perfectly well.

It is not just deleting objects either, it can be triggered by ANY function within kmail, from reading an email to clicking on a subfolder of your inbox to view its contents, emptying your wastebin, clicking on the top menu bar, whatever.

However, this is now getting serious as there are an increasingly large number of reports since 4.8.2 coming out of these types of crashes.  Attention would be welcomed :)

The crash can be reproduced every time.

-- Backtrace:
Application: KMail (kmail), signal: Segmentation fault
Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0xb5dbf740 (LWP 3615))]

Thread 4 (Thread 0xb3cc1b40 (LWP 3619)):
#0  0x00e12416 in __kernel_vsyscall ()
#1  0x01a3c96b in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/i386-linux-gnu/libpthread.so.0
#2  0x041a73dc in pthread_cond_wait () from /lib/i386-linux-gnu/libc.so.6
#3  0xb6ff2263 in ?? () from /usr/lib/i386-linux-gnu/libQtWebKit.so.4
#4  0xb6ff237f in ?? () from /usr/lib/i386-linux-gnu/libQtWebKit.so.4
#5  0x01a38d4c in start_thread () from /lib/i386-linux-gnu/libpthread.so.0
#6  0x04199ace in clone () from /lib/i386-linux-gnu/libc.so.6

Thread 3 (Thread 0xb3398b40 (LWP 3620)):
#0  0x01efb3d0 in g_mutex_lock () from /lib/i386-linux-gnu/libglib-2.0.so.0
#1  0x01ebb6b6 in g_main_context_prepare () from /lib/i386-linux-gnu/libglib-2.0.so.0
#2  0x01ebbfaf in ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0
#3  0x01ebc201 in g_main_context_iteration () from /lib/i386-linux-gnu/libglib-2.0.so.0
#4  0x00c008e7 in QEventDispatcherGlib::processEvents (this=0xb2a00468, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#5  0x00bcc50d in QEventLoop::processEvents (this=0xb3398270, flags=...) at kernel/qeventloop.cpp:149
#6  0x00bcc7a9 in QEventLoop::exec (this=0xb3398270, flags=...) at kernel/qeventloop.cpp:204
#7  0x00ab594c in QThread::exec (this=0x918a940) at thread/qthread.cpp:501
#8  0x00ab5a3b in QThread::run (this=0x918a940) at thread/qthread.cpp:568
#9  0x00ab8de0 in QThreadPrivate::start (arg=0x918a940) at thread/qthread_unix.cpp:298
#10 0x01a38d4c in start_thread () from /lib/i386-linux-gnu/libpthread.so.0
#11 0x04199ace in clone () from /lib/i386-linux-gnu/libc.so.6

Thread 2 (Thread 0xb18ffb40 (LWP 3623)):
#0  0x00a98287 in __i686.get_pc_thunk.bx () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#1  0x00c0004c in postEventSourcePrepare (s=0x9431ae0, timeout=0xb18ff0bc) at kernel/qeventdispatcher_glib.cpp:255
#2  0x01ebb872 in g_main_context_prepare () from /lib/i386-linux-gnu/libglib-2.0.so.0
#3  0x01ebbfaf in ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0
#4  0x01ebc201 in g_main_context_iteration () from /lib/i386-linux-gnu/libglib-2.0.so.0
#5  0x00c008e7 in QEventDispatcherGlib::processEvents (this=0x9433be0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00bcc50d in QEventLoop::processEvents (this=0xb18ff240, flags=...) at kernel/qeventloop.cpp:149
#7  0x00bcc7a9 in QEventLoop::exec (this=0xb18ff240, flags=...) at kernel/qeventloop.cpp:204
#8  0x00ab594c in QThread::exec (this=0x94ed5b8) at thread/qthread.cpp:501
#9  0x00ba9b5d in QInotifyFileSystemWatcherEngine::run (this=0x94ed5b8) at io/qfilesystemwatcher_inotify.cpp:248
#10 0x00ab8de0 in QThreadPrivate::start (arg=0x94ed5b8) at thread/qthread_unix.cpp:298
#11 0x01a38d4c in start_thread () from /lib/i386-linux-gnu/libpthread.so.0
#12 0x04199ace in clone () from /lib/i386-linux-gnu/libc.so.6

Thread 1 (Thread 0xb5dbf740 (LWP 3615)):
[KCrash Handler]
#7  0x07af121d in QNetworkAccessHttpBackend::replyDownloadMetaData (this=0x998ee58, hm=<error reading variable: Cannot access memory at address 0x0>, sc=0, rp=<error reading variable: Cannot access memory at address 0x0>, pu=240, db=..., contentLength=-4165406276) at access/qnetworkaccesshttpbackend.cpp:827
#8  0x07b8837d in QNetworkAccessHttpBackend::qt_static_metacall (_o=0x998ee58, _c=QMetaObject::InvokeMetaMethod, _id=6, _a=0xb2a26f40) at .moc/release-shared/moc_qnetworkaccesshttpbackend_p.cpp:91
#9  0x00bdfc01 in QMetaCallEvent::placeMetaCall (this=0xb2a270a0, object=0x998ee58) at kernel/qobject.cpp:525
#10 0x00be8c7b in QObject::event (this=0x998ee58, e=0xb2a270a0) at kernel/qobject.cpp:1195
#11 0x00f4ded4 in notify_helper (e=0xb2a270a0, receiver=0x998ee58, this=0x8d6de90) at kernel/qapplication.cpp:4559
#12 QApplicationPrivate::notify_helper (this=0x8d6de90, receiver=0x998ee58, e=0xb2a270a0) at kernel/qapplication.cpp:4531
#13 0x00f5330d in QApplication::notify (this=0xb2a270a0, receiver=0x998ee58, e=0xb2a270a0) at kernel/qapplication.cpp:4288
#14 0x002fcb61 in KApplication::notify (this=0xbff811cc, receiver=0x998ee58, event=0xb2a270a0) at ../../kdeui/kernel/kapplication.cpp:311
#15 0x00bcd97e in QCoreApplication::notifyInternal (this=0xbff811cc, receiver=0x998ee58, event=0xb2a270a0) at kernel/qcoreapplication.cpp:876
#16 0x00bd1ad8 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#17 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x8d2b150) at kernel/qcoreapplication.cpp:1500
#18 0x00bd1e0c in QCoreApplication::sendPostedEvents (receiver=0x0, event_type=0) at kernel/qcoreapplication.cpp:1393
#19 0x00c00494 in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#20 postEventSourceDispatch (s=0x8d6f1a0) at kernel/qeventdispatcher_glib.cpp:279
#21 0x01ebbd86 in g_main_context_dispatch () from /lib/i386-linux-gnu/libglib-2.0.so.0
#22 0x01ebc125 in ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0
#23 0x01ebc201 in g_main_context_iteration () from /lib/i386-linux-gnu/libglib-2.0.so.0
#24 0x00c00887 in QEventDispatcherGlib::processEvents (this=0x8d2bec0, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#25 0x01006aaa in QGuiEventDispatcherGlib::processEvents (this=0x8d2bec0, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#26 0x00bcc50d in QEventLoop::processEvents (this=0xbff810f4, flags=...) at kernel/qeventloop.cpp:149
#27 0x00bcc7a9 in QEventLoop::exec (this=0xbff810f4, flags=...) at kernel/qeventloop.cpp:204
#28 0x00bd1eba in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#29 0x00f4ba74 in QApplication::exec () at kernel/qapplication.cpp:3820
#30 0x0804a266 in ?? ()
#31 0x040c84d3 in __libc_start_main () from /lib/i386-linux-gnu/libc.so.6
#32 0x0804a6e9 in _start ()

Possible duplicates by query: bug 302222, bug 302174, bug 302020, bug 301840, bug 301561.

Reported using DrKonqi