rpm-4.1 runs with signals blocked, hoping to get to a "safe" point to exit (and close the database).
*** Bug 75696 has been marked as a duplicate of this bug. ***
There's little reason to keep this bug open anymore. The good news is that rpm-4.2-0.28nptl (probably, untested as of this moment) fixes the stale lock problem. The bad news is that you need to run a kernel that supplies /dev/futex, and a version of glibc that supplies nptl.