race condition for drop schema cascade?

I have seen this failure several times, but not consistently, on the
buildfarm member otter (Debian/MIPS) and possible on others, and am
wondering if it indicates a possible race condition on DROP SCHEMA CASCADE.

================== pgsql.30167/src/test/regress/regression.diffs ===================
*** ./expected/tablespace.out Sat Dec 11 13:05:32 2004
--- ./results/tablespace.out Sat Dec 11 14:35:24 2004
***************
*** 35,37 ****
--- 35,38 ----
NOTICE: drop cascades to table testschema.foo
-- Should succeed
DROP TABLESPACE testspace;
+ ERROR: tablespace "testspace" is not empty

======================================================================

cheers

andrew