- Replace a KASSERT() that knew too much about mutex internals with a

mtx_assert() that ensures the mutex we release during msleep() is both
  not recursed and owned by the current process.

sys/kern/kern_synch.c

@@ -424,8 +424,7 @@ msleep(ident, mtx, priority, wmesg, timo)
 	mtx_enter(&sched_lock, MTX_SPIN);
 
 	if (mtx != NULL) {
-		KASSERT(mtx->mtx_recurse == 0,
-		    ("sleeping on recursed mutex %s", mtx->mtx_description));
+		mtx_assert(mtx, MA_OWNED | MA_NOTRECURSED);
 		WITNESS_SAVE(mtx, mtx);
 		mtx_exit(mtx, MTX_DEF | MTX_NOSWITCH);
 		if (priority & PDROP)