sources: 2.6rc1 tarball
system: FreeBSD 6.3 i386, gcc 3.4.6 (system compiler)
build:  ./configure; make

it makes no difference whether test_threading is run as part of make test 
or on its own - process suspends and has to be killed (I left one run the 
best part of an hour with no progress).

a log from a verbose run:
andymac@bullseye$ ./python -E -tt Lib/test/regrtest.py -v test_threading
>logfile 2>&1
test_threading
test_PyThreadState_SetAsyncExc (test.test_threading.ThreadTests) ...   
 started worker thread
    trying nonsensical thread id
    waiting for worker thread to get started
    verifying worker hasn't exited
    attempting to raise asynch exception in worker
    waiting for worker to say it caught the exception
    all OK -- joining worker
ok
test_enumerate_after_join (test.test_threading.ThreadTests) ... ok
test_finalize_runnning_thread (test.test_threading.ThreadTests) ... ok
test_finalize_with_trace (test.test_threading.ThreadTests) ... ok
test_foreign_thread (test.test_threading.ThreadTests) ... ok
test_no_refcycle_through_target (test.test_threading.ThreadTests) ... ok
test_various_ops (test.test_threading.ThreadTests) ... task <thread 0>
will run for 26.0 usec
1 tasks are running
task <thread 1> will run for 25.7 usec
2 tasks are running
task <thread 2> will run for 28.9 usec
3 tasks are running
task <thread 3> will run for 47.1 usec
task <thread 4> will run for 19.8 usec
task <thread 5> will run for 10.0 usec
task <thread 6> will run for 25.4 usec
task <thread 7> will run for 55.5 usectasktask <thread 1> done
<thread 1> is finished. 2 tasks are running

  task <thread 2> done
<thread 2> is finished. 1 tasks are running
2 tasks are running
<thread 0> done
<thread 0> is finished. 1 tasks are running
task <thread 8> will run for 61.3 usec
2 tasks are running
3 tasks are running
task <thread 9> will run for 53.1 usec
waiting for all tasks to complete
task <thread 3> done
<thread 3> is finished. 2 tasks are running
task <thread 4> done
<thread 4> is finished. 1 tasks are running
2 tasks are running
3 tasks are running
task <thread 8> done
<thread 8> is finished. 2 tasks are running
3 tasks are running
task <thread 7> done
<thread 7> is finished. 2 tasks are running
task <thread 6> done
<thread 6> is finished. 1 tasks are running
2 tasks are running
task <thread 5> done
<thread 5> is finished. 1 tasks are running
task <thread 9> done
<thread 9> is finished. 0 tasks are running
all tasks done
ok
test_various_ops_large_stack (test.test_threading.ThreadTests) ... with
1MB thread stack size...
task <thread 0> will run for 96.9 usec
1 tasks are running
task <thread 1> will run for 99.4 usec
2 tasks are running
task <thread 2> will run for 0.8 usec
3 tasks are running
task <thread 2> done
<thread 2> is finished. 2 tasks are running
task <thread 3> will run for 89.1 usec
3 tasks are running
task <thread 4> will run for 46.8 usec
task <thread 5> will run for 13.2 usec
task <thread 6> will run for 23.8 usec
tasktask <thread 0> done
<thread 0> is finished. 2 tasks are running
task <thread 7> will run for 41.6 usec 
<thread 1> done
<thread 1> is finished. 1 tasks are running
2 tasks are running
3task <thread 8> will run for 55.8 usec
 tasks are running
waiting for all tasks to complete
task <thread 3> done
<thread 3> is finished. 2 tasks are running
task <thread 9> will run for 53.2 usec 3 tasks are running

task <thread 4> done
<thread 4> is finished. 2 tasks are running
task <thread 5> done
<thread 5> is finished. 1 tasks are running
2 tasks are running
3 tasks are running
task <thread 6> done
<thread 6> is finished. 2 tasks are running
3 tasks are running
task <thread 7> done
<thread 7> is finished. 2 tasks are running
task <thread 8> done
<thread 8> is finished. 1 tasks are running
task <thread 9> done
<thread 9> is finished. 0 tasks are running
all tasks done
ok
test_various_ops_small_stack (test.test_threading.ThreadTests) ... with
256kB thread stack size...
task <thread 0> will run for 54.5 usec
1 tasks are running
task <thread 1> will run for 5.2 usec
2 tasks are running
task <thread 2> will run for 2.1 usec
3 tasks are running
task <thread 3> will run for 40.5 usec
task <thread 4> will run for 55.9 usec
task <thread 5> will run for 77.1 usec
task <thread 6> will run for 82.4 usec
task <thread 0> done
<thread 0> is finished. 2 tasks are running
task <thread 1> done
<thread 1> is finished. 1 tasks are running
2 tasks are running
task <thread 7> will run for 100.0 usec
task <thread 8> will run for 64.5 usec
3 tasks are running
waiting for all tasks to complete
task <thread 2> done
<thread 2> is finished. 2 tasks are running
3 tasks are running
task <thread 9> will run for 76.7 usec
task <thread 3> done
<thread 3> is finished. 2 tasks are running
task <thread 4> done
<thread 4> is finished. 1 tasks are running
2 tasks are running
3 tasks are running
task <thread 5> done
<thread 5> is finished. 2 tasks are running
3 tasks are running
task <thread 7> done
<thread 7> is finished. 2 tasks are running
task <thread 6> done
<thread 6> is finished. 1 tasks are running
2 tasks are running
task <thread 8> done
<thread 8> is finished. 1 tasks are running
task <thread 9> done
<thread 9> is finished. 0 tasks are running
all tasks done
ok
test_1_join_on_shutdown (test.test_threading.ThreadJoinOnShutdown) ... ok
test_2_join_in_forked_process (test.test_threading.ThreadJoinOnShutdown)
... ok
test_3_join_in_forked_from_thread
(test.test_threading.ThreadJoinOnShutdown) ... Fatal error 'mutex is on
list' at line 540 in file /usr/src/lib/libpthread/thread/thr_mutex.c
(errno = 0)

Exception in thread Thread-1:
Traceback (most recent call last):
  File "/home/andymac/build/Python-2.6rc1/Lib/threading.py", line 522,
in __bootstrap_inner
    self.run()
  File "/home/andymac/build/Python-2.6rc1/Lib/threading.py", line 477,
in run
    self.__target(*self.__args, **self.__kwargs)
  File "<string>", line 14, in worker
OSError: [Errno 4] Interrupted system call

Exception KeyboardInterrupt in <module 'threading' from
'/home/andymac/build/Python-2.6rc1/Lib/threading.pyc'> ignored