On aix 5.2 (ML1), if I remove a runnning program (via rm) and then run
procstack on its pid, it hangs chowing on cpu. If I link the a.out
via "ln /proc//object/a.out ", the procstack
will complete normally.

Has anyone else seen this, or know of an APAR that addresses it? Does
it still happen under 5.3?

A warning if you try this:
don't attach to said process while it has a procstack running against
it.
In the process of doing this, I discovered APAR IY89277:
"DBX PTATTACH SHOULD FAIL IF TARGET PROC IS UNDER PROCFS"
when i tried to attach with dbx to the said removed process.
now i have a stuck process and a stuck dbx that i can't remove without
rebooting.