Bug#476217: psi vs Qt4.4.0-3 segmentation fault

[Jan Niehusmann <jan@gondor.com>]

Hi Sune,

(Cc: to all the other addresses, because just removing the 3 patches may
not give meaningfull results.)

On Sun, Jul 06, 2008 at 05:51:24PM +0200, Sune Vuorela wrote:
> Try on a updated unstable system:
> 
> apt-get source qt4-x11 
> open debian/patches/series with your favourite editor and 
> comment the following 3 patches: (add a # at the beginning of the line)
> 72_generic_arch_atomic_header_fix.diff
> 73_from4.4.1_no_AAAA_when_ipv6_disabled.diff
> 0230-qtextcontrol-selectnextword.diff
> 
> build. install. test.

I just did a similar thing: I did not comment the three patches, but
just added a single if(isnan(...)) abort(); for debugging purposes. But
now, the segfault doesn't occur any more.

AFAICT, there are only two possible explanations: Either the bug doesn't
happen with my toolchain (perhaps the compiler version is different than
the one used to compile the debian qt package?), or it's some
missoptimization by gcc which went away with the additional code line.

Next, I'll try it with an unmodified source. 

If this still 'fixes' the problem, the core of the bug is much more
difficult to find. The good news would be, that a simple recompile
of qt on an up-to-date system probably would solve (or work around)
the segfault.

Jan