@font-face in CSS causes segfault in QApplication::fontDatabaseChanged() on exit

When using CSS-Font:
@font-face

within a Page in the WebKit-Component, QT segfaults on exit.

If the @font-face-declaration is removed, everything is fine.

I thought, that this is not a webkitbug, since the error is in QApplication::fontDatabaseChanged().

0 QtCore 0x02a3be01 QMetaObject::activate(QObject*, QMetaObject const*, int, void**) + 113
1 QtGui 0x01f274a2 QApplication::fontDatabaseChanged() + 50
2 QtGui 0x020ca9e6 QFontDatabase::removeApplicationFont(int) + 390
3 QtWebKit 0x0045a841 WebCore::CachedFont::allClientsRemoved() + 33
4 QtWebKit 0x0045d38a WebCore::CachedResource::removeClient(WebCore::CachedResourceClient*) + 170
5 QtWebKit 0x00254940 WebCore::CSSFontFaceSource::~CSSFontFaceSource() + 48
6 QtWebKit 0x0024cf5e void WTF::deleteAllValues<WebCore::CSSFontFaceSource*, 0ul>(WTF::Vector<WebCore::CSSFontFaceSource*, 0ul> const&) + 46
7 QtWebKit 0x0024cded WebCore::CSSFontFace::~CSSFontFace() + 29
8 QtWebKit 0x002881af WTF::Vector<WTF::RefPtr<WebCore::CSSFontFace>, 1ul>::shrink(unsigned long) + 79
9 QtWebKit 0x00287b3b WebCore::CSSSegmentedFontFace::~CSSSegmentedFontFace() + 139
...
26 QtCore 0x02a3a08c QObjectPrivate::deleteChildren() + 76
27 QtCore 0x02a3c137 QObject::~QObject() + 791
28 QtGui 0x01f29027 QApplication::~QApplication() + 1399
29 myapp 0x000097ce main + 1312 (main.cpp:55)