Crash in QX11PaintEngine::drawPixmap (probably when image conversion failed)

QX11PaintEngine::drawPixmap accesses the X11 pixmap or xrender data, without checking if the pixmap is valid. The image conversion could have failed, for example when the graphics drivers failed to allocated memory for the pixmap.

For details, see https://bugs.kde.org/show_bug.cgi?id=230490

– Backtrace (Reduced):
#7 0xb651c086 in QX11PaintEngine::drawPixmap (this=0x9c96698, r=@0xbfd16990,
px=@0xbfd166d8, _sr=@0xbfd166a8) at painting/qpaintengine_x11.cpp:1919
#8 0xb6451669 in QPaintEngine::drawImage (this=0x9c96698, r=@0xbfd16990,
image=@0xbfd16b34, sr=@0xbfd169b0, flags=

) at
painting/qpaintengine.cpp:624
#9 0xb651a1c4 in QX11PaintEngine::drawImage (this=0x9c96698, r=@0xbfd16990,
image=@0xbfd16b34, sr=@0xbfd169b0, flags=

) at
painting/qpaintengine_x11.cpp:1893
#10 0xb6469636 in QPainterPrivate::draw_helper (this=0x9cdeb70,
originalPath=@0xbfd16c24, op=<value optimized out>) at
painting/qpainter.cpp:484
#11 0xb646bc13 in QPainter::drawRects (this=0xbfd16fe0, rects=0xbfd16f08,
rectCount=1) at painting/qpainter.cpp:3571