bug#9089: pipe failure with cat and head of coreutils 6.12

[Philipp Thomas]

I'm trying to track down a bug in cat of coreutils 6.12. Doing 

cat /var/log/Xorg.0.log | head -n70

under ksh consistently fails with 'cat: write error: Connection reset by
peer'.  It does not fail when run under bash and it does not fail in current
coreutils .  It seems that ksh implementing pipes by socketpair(2) is the
reason for this failure.

Does somebody have a hint how to track this down? When trying to use strace
it won't fail and I don't know how to get this to run under gdb.

Philipp