my system has recently updated to QT 5.12.5 and that now causes the speedcrunch application to crash. When I run it with gdb I see the following stack trace: Thread 1 "speedcrunch" received signal SIGSEGV, Segmentation fault. 0x0000000000000000 in ?? () (gdb) bt #0 0x0000000000000000 in ?? () #1 0x00007ffff722ac20 in QPainter::fillRect(QRect const&, QBrush const&) () from /usr/lib64/libQt5Gui.so.5 #2 0x00007ffff77a0b24 in QWidgetPrivate::paintBackground(QPainter*, QRegion const&, QFlags<QWidgetPrivate::DrawWidgetFlag>) const () from /usr/lib64/libQt5Widgets.so.5 #3 0x00007ffff77a4772 in QWidgetPrivate::drawWidget(QPaintDevice*, QRegion const&, QPoint const&, QFlags<QWidgetPrivate::DrawWidgetFlag>, QPainter*, QWidgetRepaintManager*) () from /usr/lib64/libQt5Widgets.so.5 #4 0x00007ffff777705e in ?? () from /usr/lib64/libQt5Widgets.so.5 #5 0x00007ffff77775fa in ?? () from /usr/lib64/libQt5Widgets.so.5 #6 0x00007ffff77ccfc8 in ?? () from /usr/lib64/libQt5Widgets.so.5 #7 0x00007ffff77643fe in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5 #8 0x00007ffff6ac12e8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib64/libQt5Core.so.5 #9 0x00007ffff6f31f0d in QGuiApplicationPrivate::processExposeEvent(QWindowSystemInterfacePrivate::ExposeEvent*) () from /usr/lib64/libQt5Gui.so.5 #10 0x00007ffff6f03feb in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Gui.so.5 #11 0x00007ffff33421b3 in ?? () from /usr/lib64/libQt5XcbQpa.so.5 #12 0x00007ffff6abfd4b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5 #13 0x00007ffff6ac8170 in QCoreApplication::exec() () from /usr/lib64/libQt5Core.so.5 #14 0x00005555555ab6ee in main () I initially did rebuild all dependencies of speedcrunch, but I have the same crashing result. I have then rebuild QT 5.15.11 and the speedcrunch program runs as expected. Reproducible: Always Steps to Reproduce: 1. start the speedcrunch program.
Created attachment 883968 [details] emerge info
Can you try with debugging symbols for dev-qt/* (no need for qtwebengine) and speedcrunch if not already got them? Maybe try with -O2 at the same time and I imagine it'll go away. fillRect is suspicious and it's been the source of problems before. Think it came up in anotehr bug recently but not sure which.
here's a screenshot of my gdb session. I don't see anything wrong with the "d" or "d->extended" objects, but it seems that the virtual function call to fillRect() is crashing. I don't know how to debug this, but I assume that this version of QT 5.15.12 simply doesn't set up these C++ objects correctly. It's probably not a gentoo bug, but rather a QT bug. But if you see more crash reports in Gentoo with this version of QT, you should remove this QT version from the list of stable versions. I've looked at the qt.io bug tracker, but currently no open issue for a crash when calling fillRect(). Maybe I should create a bug report for QT developers. ┌─/usr/src/debug/dev-qt/qtgui-5.15.12/qtbase-everywhere-src-5.15.12/src/gui/painting/qpainter.cpp──────────────────────────────────────────────────────────────────┐ │ 6983 \fn void QPainter::fillRect(const QRect &rectangle, const QBrush &brush) │ │ 6984 \overload │ │ 6985 │ │ 6986 Fills the given \a rectangle with the specified \a brush. │ │ 6987 */ │ │ 6988 │ │ 6989 void QPainter::fillRect(const QRect &r, const QBrush &brush) │ │ 6990 { │ │ 6991 Q_D(QPainter); │ │ 6992 │ │ 6993 if (!d->engine) │ │ 6994 return; │ │ 6995 │ │ 6996 if (d->extended && !needsEmulation(brush)) { │ │ > 6997 d->extended->fillRect(r, brush); │ │ 6998 return; │ │ 6999 } │ │ 7000 │ │ 7001 QPen oldPen = pen(); │ │ 7002 QBrush oldBrush = this->brush(); │ │ 7003 setPen(Qt::NoPen); │ │ 7004 if (brush.style() == Qt::SolidPattern) { │ │ 7005 d->colorBrush.setStyle(Qt::SolidPattern); │ │ 7006 d->colorBrush.setColor(brush.color()); │ │ 7007 setBrush(d->colorBrush); │ │ 7008 } else { │ │ 7009 setBrush(brush); │ │ 7010 } │ │ 7011 │ │ 7012 drawRect(r); │ └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘ multi-thre Thread 0x7ffff74911 In: QPainter::fillRect L6997 PC: 0x7ffff722ac20 (gdb) p d $1 = (QPainterPrivate * const) 0x555555c0c4e0 (gdb) p d->extended $2 = (QPaintEngineEx *) 0x555555b6a110 (gdb) p d->extended->fillRect cannot resolve overloaded method `fillRect': no arguments supplied (gdb) p d->extended->fillRect(r,brush) Cannot resolve method QPaintEngineEx::fillRect to any overloaded instance The type: 'QPaintEngineEx *' isn't fully known to GDB. Please cast it directly to the desired typed in the function call. (gdb) p *(d->extended) $3 = {<QPaintEngine> = {_vptr.QPaintEngine = 0x7ffff747a330 <vtable for QRasterPaintEngine+16>, state = 0x555555c1de38, gccaps = {i = 4294967295}, active = 1, selfDestruct = 0, extended = 1, d_ptr = {d = 0x555555a51910}}, <No data fields>}
https://bugreports.qt.io/browse/QTBUG-122064
Qt don't maintain the 5.15.x for FOSS releases anymore. We'd need to first reproduce this with Qt 6 and/or report it to KDE's Qt5PatchCollection. Although if it were reproducible without any of the backports, maybe Qt would be interested. Anyway, let's see what asturm says.
