Created attachment 187315 [details]
Crash reproducable file

SUMMARY
I've found a specific RTF file that seems to consistently crash when kioworker tries to make a thumbnail for it.

STEPS TO REPRODUCE
1. Download file
2. Browse to it in Dolphin

OBSERVED RESULT
kioworker crashes

EXPECTED RESULT
No crash

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.5.3
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.1
Kernel Version: 6.17.9-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 32 × AMD Ryzen 9 9950X3D 16-Core Processor
Memory: 64 GiB of RAM (60.4 GiB usable)
Graphics Processor 1: NVIDIA GeForce RTX 5080/PCIe/SSE2
Graphics Processor 2: NVIDIA GeForce RTX 5080/PCIe/SSE2

ADDITIONAL INFORMATION
Backtrace:
#0  __pthread_kill_implementation (threadid=<optimized out>, signo=signo@entry=11, no_tid=no_tid@entry=0) at pthread_kill.c:44
#1  0x00007f41090989d3 in __pthread_kill_internal (threadid=<optimized out>, signo=11) at pthread_kill.c:89
#2  0x00007f410903e3a0 in __GI_raise (sig=11) at ../sysdeps/posix/raise.c:26
#3  0x00007f4109a8ce57 in KCrash::defaultCrashHandler (sig=11) at /usr/src/debug/kcrash/kcrash-6.20.0/src/kcrash.cpp:605
#4  0x00007f410903e4d0 in <signal handler called> () at /usr/lib/libc.so.6
#5  0x00007f40d540a5db in QStringDecoder::decodeAsString (this=0x7ffc1b48fbd0, in=...) at /usr/include/qt6/QtCore/qstringconverter.h:141
#6  QStringDecoder::EncodedData<QByteArray const&>::operator QString (this=<optimized out>) at /usr/include/qt6/QtCore/qstringconverter.h:105
#7  RtfReader::TextDocumentRtfOutput::appendText (this=0x7ffc1b48ff30, text=...) at /usr/src/debug/calligra/calligra-25.08.3/filters/words/rtf/import/3rdparty/rtf-qt/src/TextDocumentRtfOutput.cpp:52
#8  0x00007f40d540650d in RtfReader::Reader::parseDocument (this=this@entry=0x7ffc1b48fec0) at /usr/src/debug/calligra/calligra-25.08.3/filters/words/rtf/import/3rdparty/rtf-qt/src/rtfreader.cpp:307
#9  0x00007f40d54070e9 in RtfReader::Reader::parseFile (this=this@entry=0x7ffc1b48fec0) at /usr/src/debug/calligra/calligra-25.08.3/filters/words/rtf/import/3rdparty/rtf-qt/src/rtfreader.cpp:96
#10 0x00007f40d5407140 in RtfReader::Reader::parseTo (this=this@entry=0x7ffc1b48fec0, output=output@entry=0x7ffc1b48ff30) at /usr/src/debug/calligra/calligra-25.08.3/filters/words/rtf/import/3rdparty/rtf-qt/src/rtfreader.cpp:86
#11 0x00007f40f392f9f2 in RTFImport::convert (this=0x55c49cb89fa0, from=<optimized out>, to=<optimized out>) at /usr/src/debug/calligra/calligra-25.08.3/filters/words/rtf/import/rtfimport.cpp:63
#12 0x00007f40fcdf3ba7 in CalligraFilter::ChainLink::invokeFilter (this=0x55c49cb92390, parentChainLink=<optimized out>) at /usr/src/debug/calligra/calligra-25.08.3/libs/main/KoFilterChainLink.cpp:75
#13 0x00007f40fcde9dda in KoFilterChain::invokeChain (this=0x55c49cb65140) at /usr/src/debug/calligra/calligra-25.08.3/libs/main/KoFilterChain.cpp:89
#14 0x00007f40fcde4139 in KoFilterManager::importDocument (this=0x55c49c90c050, url=..., documentMimeType=<optimized out>, status=@0x7ffc1b4905e4: KoFilter::OK) at /usr/src/debug/calligra/calligra-25.08.3/libs/main/KoFilterManager.cpp:159
#15 0x00007f40fcdbac06 in KoDocument::openFile (this=0x55c49c9b7c40) at /usr/src/debug/calligra/calligra-25.08.3/libs/main/KoDocument.cpp:1439
#16 0x00007f40fcdaf58c in KoDocument::Private::openFile (this=this@entry=0x55c49c9b87a0) at /usr/src/debug/calligra/calligra-25.08.3/libs/main/KoDocument.cpp:272
#17 0x00007f40fcdaf76e in KoDocument::Private::openLocalFile (this=0x55c49c9b87a0) at /usr/src/debug/calligra/calligra-25.08.3/libs/main/KoDocument.cpp:294
#18 0x00007f40fcdb99d2 in KoDocument::openUrlInternal (this=0x55c49c9b7c40, url=...) at /usr/src/debug/calligra/calligra-25.08.3/libs/main/KoDocument.cpp:2651
#19 0x00007f40fcdb51a5 in KoDocument::openUrl (this=0x55c49c9b7c40, _url=...) at /usr/src/debug/calligra/calligra-25.08.3/libs/main/KoDocument.cpp:1252
#20 0x00007f4103b50ac6 in CalligraCreator::create (this=this@entry=0x55c49c8d6fa0, request=...) at /usr/src/debug/calligra/calligra-25.08.3/extras/thumbnail/calligracreator.cpp:93
#21 0x00007f4109c42f2f in ThumbnailProtocol::createThumbnail (this=this@entry=0x7ffc1b491180, thumbCreator=thumbCreator@entry=0x55c49c95ed50, filePath=..., width=width@entry=128, height=height@entry=128, thumbnail=...) at /usr/src/debug/kio-extras/kio-extras-25.08.3/thumbnail/thumbnail.cpp:882
#22 0x00007f4109c499cc in ThumbnailProtocol::get (this=<optimized out>, url=<optimized out>) at /usr/src/debug/kio-extras/kio-extras-25.08.3/thumbnail/thumbnail.cpp:340
#23 0x00007f4109b1b4e0 in KIO::WorkerSlaveBaseBridge::get (this=0x55c49ca94720, url=<optimized out>) at /usr/src/debug/kio/kio-6.20.0/src/core/workerbase_p.h:71
#24 0x00007f4109b1aecf in KIO::SlaveBase::dispatch (this=0x55c49ca94720, command=67, data=...) at /usr/src/debug/kio/kio-6.20.0/src/core/slavebase.cpp:1121
#25 0x00007f4109b1b3de in KIO::SlaveBase::dispatchLoop() [clone .constprop.0] (this=0x55c49ca94720) at /usr/src/debug/kio/kio-6.20.0/src/core/slavebase.cpp:330
#26 0x00007f4109b1cafd in KIO::WorkerBase::dispatchLoop (this=<optimized out>) at /usr/src/debug/kio/kio-6.20.0/src/core/workerbase.cpp:27
#27 0x00007f4109c44793 in kdemain (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/kio-extras/kio-extras-25.08.3/thumbnail/thumbnail.cpp:208
#28 0x000055c48033c1e2 in main (argc=<optimized out>, argv=0x7ffc1b491eb8) at /usr/include/qt6/QtCore/qvarlengtharray.h:90

I get a similar crash trying to open the RDF file in Okular as well.