Application: konqueror (4.11.4)
KDE Platform Version: 4.11.4
Qt Version: 4.8.5
Operating System: Linux 3.12.5-302.fc20.x86_64 x86_64
Distribution: "Fedora release 20 (Heisenbug)"

-- Information about the crash:
- What I was doing when the application crashed:
Surfing the net,
Was on youtube abd pressed the back button.
FC20 with all latest updates.

The crash can be reproduced sometimes.

-- Backtrace:
Application: Konqueror (konqueror), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
81	T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
[Current thread is 1 (Thread 0x7fd31e99e8c0 (LWP 13557))]

Thread 3 (Thread 0x7fd2cfd93700 (LWP 13559)):
#0  0x0000003f896eaa8d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x0000003f8d6495b4 in g_main_context_poll (priority=2147483647, n_fds=1, fds=0x7fd2c80013e0, timeout=8968, context=0x7fd2c80009c0) at gmain.c:4007
#2  g_main_context_iterate (context=context@entry=0x7fd2c80009c0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at gmain.c:3708
#3  0x0000003f8d6496dc in g_main_context_iteration (context=0x7fd2c80009c0, may_block=1) at gmain.c:3774
#4  0x0000003f937b31a6 in QEventDispatcherGlib::processEvents (this=0x7fd2c80008e0, flags=...) at kernel/qeventdispatcher_glib.cpp:427
#5  0x0000003f9378312f in QEventLoop::processEvents (this=this@entry=0x7fd2cfd92d10, flags=...) at kernel/qeventloop.cpp:149
#6  0x0000003f9378347d in QEventLoop::exec (this=this@entry=0x7fd2cfd92d10, flags=...) at kernel/qeventloop.cpp:204
#7  0x0000003f93679bdf in QThread::exec (this=<optimized out>) at thread/qthread.cpp:536
#8  0x0000003f9367c3df in QThreadPrivate::start (arg=0x1a01900) at thread/qthread_unix.cpp:338
#9  0x0000003f89e07f33 in start_thread (arg=0x7fd2cfd93700) at pthread_create.c:309
#10 0x0000003f896f4ead in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7fd2ce0eb700 (LWP 13560)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x0000003fb2abd23d in JSC::BlockAllocator::blockFreeingThreadMain (this=0x1f14e78) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/heap/BlockAllocator.cpp:128
#2  0x0000003fb2dafc56 in WTF::wtfThreadEntryPoint (param=0x1b15000) at /usr/src/debug/webkit-qtwebkit-23/Source/WTF/wtf/ThreadingPthreads.cpp:196
#3  0x0000003f89e07f33 in start_thread (arg=0x7fd2ce0eb700) at pthread_create.c:309
#4  0x0000003f896f4ead in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7fd31e99e8c0 (LWP 13557)):
[KCrash Handler]
#6  get (this=0x98000002bad170) at /usr/src/debug/webkit-qtwebkit-23/Source/WTF/wtf/RefPtr.h:58
#7  impl (this=0x98000002bad170) at /usr/src/debug/webkit-qtwebkit-23/Source/WTF/wtf/text/WTFString.h:163
#8  impl (this=0x98000002bad170) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/runtime/Identifier.h:56
#9  captures (ident=..., this=0x2c46070) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/parser/Nodes.h:1340
#10 JSC::BytecodeGenerator::BytecodeGenerator (this=0x2bb2af0, globalData=..., functionBody=0x2c46070, codeBlock=<optimized out>, debuggerMode=<optimized out>, profilerMode=<optimized out>) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp:410
#11 0x0000003fb2c8ee57 in JSC::CodeCache::generateFunctionCodeBlock (this=<optimized out>, globalData=..., executable=executable@entry=0x7fd2bc62ea80, source=..., kind=kind@entry=JSC::CodeForCall, debuggerMode=debuggerMode@entry=JSC::DebuggerOff, profilerMode=JSC::ProfilerOff, error=...) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/runtime/CodeCache.cpp:124
#12 0x0000003fb2c8fa45 in JSC::CodeCache::getFunctionCodeBlock (this=<optimized out>, globalData=..., executable=executable@entry=0x7fd2bc62ea80, source=..., kind=kind@entry=JSC::CodeForCall, debuggerMode=debuggerMode@entry=JSC::DebuggerOff, profilerMode=JSC::ProfilerOff, error=...) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/runtime/CodeCache.cpp:135
#13 0x0000003fb2a801e5 in JSC::UnlinkedFunctionExecutable::codeBlockFor (this=0x7fd2bc62ea80, globalData=..., source=..., specializationKind=specializationKind@entry=JSC::CodeForCall, debuggerMode=debuggerMode@entry=JSC::DebuggerOff, profilerMode=<optimized out>, error=...) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/bytecode/UnlinkedCodeBlock.cpp:126
#14 0x0000003fb2cb17fd in JSC::FunctionExecutable::produceCodeBlockFor (this=0x7fd2ccb24780, scope=<optimized out>, specializationKind=JSC::CodeForCall, exception=@0x7fffc45c99a0: 0x0) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/runtime/Executable.cpp:500
#15 0x0000003fb2cb4fae in JSC::FunctionExecutable::compileForCallInternal (this=this@entry=0x7fd2ccb24780, exec=exec@entry=0x7fd2cd4cc088, scope=<optimized out>, jitType=JSC::JITCode::BaselineJIT, bytecodeIndex=bytecodeIndex@entry=4294967295) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/runtime/Executable.cpp:526
#16 0x0000003fb2c0bcd3 in compileForCall (scope=<optimized out>, exec=0x7fd2cd4cc088, this=0x7fd2ccb24780) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/runtime/Executable.h:588
#17 compileFor (kind=JSC::CodeForCall, scope=<optimized out>, exec=0x7fd2cd4cc088, this=0x7fd2ccb24780) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/runtime/Executable.h:646
#18 setUpCall (callLinkInfo=0x25e56f8, calleeAsValue=..., kind=JSC::CodeForCall, pc=0x27e9700, execCallee=0x7fd2cd4cc088) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp:1421
#19 genericCall (kind=JSC::CodeForCall, pc=0x27e9700, exec=<optimized out>) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp:1463
#20 JSC::LLInt::llint_slow_path_call (exec=<optimized out>, pc=0x27e9700) at /usr/src/debug/webkit-qtwebkit-23/Source/JavaScriptCore/llint/LLIntSlowPaths.cpp:1469
#21 0x0000003fb2c14582 in llint_op_call () from /lib64/libQtWebKit.so.4
#22 0x00007fd2ccb24c80 in ?? ()
#23 0x0000000000000000 in ?? ()

Reported using DrKonqi