HelenOS sources

DEADLOCK_THRESHOLD  665 kernel/generic/src/ipc/ipc.c 			DEADLOCK_PROBE(p_phonelck, DEADLOCK_THRESHOLD);
DEADLOCK_THRESHOLD  232 kernel/generic/src/mm/as.c 		DEADLOCK_PROBE(p_asidlock, DEADLOCK_THRESHOLD);
DEADLOCK_THRESHOLD 1637 kernel/generic/src/mm/as.c 		DEADLOCK_PROBE(p_asidlock, DEADLOCK_THRESHOLD);
DEADLOCK_THRESHOLD  104 kernel/generic/src/synch/spinlock.c 		if (i++ > DEADLOCK_THRESHOLD) {
HelenOS homepage, sources at GitHub