Index: kern/subr_sleepqueue.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/subr_sleepqueue.c,v
retrieving revision 1.43
diff -u -r1.43 subr_sleepqueue.c
--- kern/subr_sleepqueue.c	25 Jan 2008 19:44:46 -0000	1.43
+++ kern/subr_sleepqueue.c	7 Feb 2008 06:19:22 -0000
@@ -801,7 +801,7 @@
 	if (TD_IS_SLEEPING(td) && TD_ON_SLEEPQ(td)) {
 		wchan = td->td_wchan;
 		sc = SC_LOOKUP(wchan);
-		MPASS(td->td_lock == &sc->sc_lock);
+		THREAD_LOCKPTR_ASSERT(td, &sc->sc_lock);
 		sq = sleepq_lookup(wchan);
 		MPASS(sq != NULL);
 		td->td_flags |= TDF_TIMEOUT;
Index: kern/subr_turnstile.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/subr_turnstile.c,v
retrieving revision 1.171
diff -u -r1.171 subr_turnstile.c
--- kern/subr_turnstile.c	6 Feb 2008 01:02:13 -0000	1.171
+++ kern/subr_turnstile.c	7 Feb 2008 06:19:23 -0000
@@ -180,7 +180,7 @@
 	THREAD_LOCK_ASSERT(td, MA_OWNED);
 	pri = td->td_priority;
 	ts = td->td_blocked;
-	MPASS(td->td_lock == &ts->ts_lock);
+	THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
 	/*
 	 * Grab a recursive lock on this turnstile chain so it stays locked
 	 * for the whole operation.  The caller expects us to return with
@@ -267,7 +267,7 @@
 		 */
 		ts = td->td_blocked;
 		MPASS(ts != NULL);
-		MPASS(td->td_lock == &ts->ts_lock);
+		THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
 		/* Resort td on the list if needed. */
 		if (!turnstile_adjust_thread(ts, td)) {
 			mtx_unlock_spin(&ts->ts_lock);
@@ -308,7 +308,7 @@
 	 * It needs to be moved if either its priority is lower than
 	 * the previous thread or higher than the next thread.
 	 */
-	MPASS(td->td_lock == &ts->ts_lock);
+	THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
 	td1 = TAILQ_PREV(td, threadqueue, td_lockq);
 	td2 = TAILQ_NEXT(td, td_lockq);
 	if ((td1 != NULL && td->td_priority < td1->td_priority) ||
@@ -422,7 +422,7 @@
 	 */
 	ts = td->td_blocked;
 	MPASS(ts != NULL);
-	MPASS(td->td_lock == &ts->ts_lock);
+	THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
 	mtx_assert(&ts->ts_lock, MA_OWNED);
 
 	/* Resort the turnstile on the list. */
@@ -645,7 +645,7 @@
 	td = turnstile_first_waiter(ts);
 	MPASS(td != NULL);
 	MPASS(td->td_proc->p_magic == P_MAGIC);
-	MPASS(td->td_lock == &ts->ts_lock);
+	THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
 
 	/*
 	 * Update the priority of the new owner if needed.
@@ -740,7 +740,7 @@
 		CTR4(KTR_LOCK, "%s: td %d blocked on [%p] %s", __func__,
 		    td->td_tid, lock, lock->lo_name);
 
-	MPASS(td->td_lock == &ts->ts_lock);
+	THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
 	SCHED_STAT_INC(switch_turnstile);
 	mi_switch(SW_VOL, NULL);
 
@@ -918,7 +918,7 @@
 		td = TAILQ_FIRST(&pending_threads);
 		TAILQ_REMOVE(&pending_threads, td, td_lockq);
 		thread_lock(td);
-		MPASS(td->td_lock == &ts->ts_lock);
+		THREAD_LOCKPTR_ASSERT(td, &ts->ts_lock);
 		MPASS(td->td_proc->p_magic == P_MAGIC);
 		MPASS(TD_ON_LOCK(td));
 		TD_CLR_LOCK(td);
Index: sys/proc.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/proc.h,v
retrieving revision 1.502
diff -u -r1.502 proc.h
--- sys/proc.h	6 Feb 2008 01:02:12 -0000	1.502
+++ sys/proc.h	7 Feb 2008 06:19:27 -0000
@@ -313,6 +313,17 @@
 		mtx_assert(__m, (type));				\
 } while (0)
 
+#ifdef INVARIANTS
+#define	THREAD_LOCKPTR_ASSERT(td, lock)					\
+do {									\
+	struct mtx *__m = (td)->td_lock;				\
+	KASSERT((__m == &blocked_lock || __m == (lock)),		\
+	    ("Thread %p lock %p does not match %p", td, __m, (lock)));	\
+} while (0)
+#else
+#define	THREAD_LOCKPTR_ASSERT(td, lock)
+#endif
+
 /*
  * Flags kept in td_flags:
  * To change these you MUST have the scheduler lock.