[Qt-interest] Application compiled with Qt 4.5.1 causes X11 server to die

[Srdjan Todorovic]

Hello everyone,

I've got an application that paints many points on a QWidget, using
QPainter::drawPolygon(), and when run with the GSHHS high detail data
set, causes X11 under Linux to restart (screen goes blank for a
second, then I am presented with the KDM login prompt).

I was told on IRC that I had to get the latest nVidia drivers, which I
have now done, but the problem still persists.

I'm trying to cut down the problem to a smallish test case, but this
problem is only triggered when a certain 20MB file is read (any
testers will need to download the GSHHS dataset from
ftp://ftp.soest.hawaii.edu/pwessel/gshhs/). Tried to squish all the
classes into one file, but I dont think moc likes multiple objects
(one of which is a Q_OBJECT) in one file.

I could attach a compressed tarball (4.5kB) and send to the list if it
would help, if it's OK with the list admins (spam/bandwidth/netiquette
objections etc.).

I've narrowed down the crash to one line in my code (but the cause
might not be exactly at that place):

   _pPainter->drawPolygon(pPoints, nPoints, Qt::WindingFill);

nPoints is usually 4. The above line, when commented, does not cause
X11 server crash.

This code used to work in Qt 4.3 (or 4.2).

Other things that might be of use:
   Xorg-server-1.4.2
   Slamd64 12.2   (64bit userland and kernel)
   NVIDIA x86_64 version 180.51
   g++ (GCC) 4.2.4

Tomorrow evening I'll be in a position to compile and test an earlier
Qt4 release.

Any ideas what could be causing this?

Many thanks,
Srdjan