Various layout tests crash with the DRT and Qt 5 due to a subtle font-config issue. The backtraces indicate that an empty font-family causes crashes with atomic string. The root cause is the fact that the default font family returned by Qt is an empty string, which is not a valid situation. In Qt 4.8 the default font / family was "Helvetica". In Qt 5 the default is queried from font-config by doing the programmatic equivalent of running "fc-match" on the commandline, in src/platformsupport/fontdatabases/fontconfig/qfontconfigdatabase.cpp. You can verify this by calling 'ltrace fc-match' and comparing the font-config commands to what's being done in QFontconfigDatabase::resolveFontFamilyAlias. In a normal "Linux" system the default is defined through a rule like this (from /etc/fonts/conf.d/49-sansserif.conf) : <!-- If the font still has no generic name, add sans-serif --> <match target="pattern"> <test qual="all" name="family" compare="not_eq"> <string>sans-serif</string> </test> <test qual="all" name="family" compare="not_eq"> <string>serif</string> </test> <test qual="all" name="family" compare="not_eq"> <string>monospace</string> </test> <edit name="family" mode="append_last"> <string>sans-serif</string> </edit> </match> This ensures the "last resort fallback", and indeed this is missing in _our_ fonts.conf in Tools/DumpRenderTree/qt/fonts.conf.
Created attachment 121825 [details] Patch
Comment on attachment 121825 [details] Patch LGTM,r=me.
Committed r104551: <http://trac.webkit.org/changeset/104551>
Comment on attachment 121825 [details] Patch oops, landed manually