I am trying the small attached program on FreeBSD 6.3 (amd64, SCHED_4BSD) and 7-STABLE (i386, SCHED_ULE), both with libthr as threads library and on both it produces "BROKEN" message. I compile this program as follows: cc sched_test.c -o sched_test -pthread I believe that the behavior I observe is broken because: if thread #1 releases a mutex and then tries to re-acquire it while thread #2 was already blocked waiting on that mutex, then thread #1 should be "queued" after thread #2 in mutex wai...