I encountered the following failure during kernel rpm build:

./scripts/modsign/modsign.sh: line 46: 18123 Segmentation fault      gpg --no-greeting $KEYFLAGS -b $module.out
error: Bad exit status from /var/tmp/rpm-tmp.64287 (%build)

RPM build errors:
    Bad exit status from /var/tmp/rpm-tmp.64287 (%build)

Finally get to know it is a bug of the linux kernel exec-shield patch. It exists in FC6, Fedora 7 and RHEL5. But the update kernels have fixed it.

Reference

1. Redhat Bugzilla Bug 246623: applications compiled with pie flag crash randomly.
2. Ingo Molnar's Exec Shield patch web page.