--- /usr/src/sys/kern/kern_lock.c	Wed Jan  9 01:02:43 2008
+++ sys/kern/kern_lock.c	Fri Jan 11 12:49:01 2008
@@ -545,6 +545,9 @@
 {
 	struct thread *td;
 
+	/* If the kernel panicked, avoid to panic again on assertions. */
+	if (panicstr != NULL)
+		return;
 	td = curthread;
 	KASSERT(lkp->lk_exclusivecount,
 	    ("%s: %p lockmgr must be exclusively locked", __func__, lkp));
@@ -555,7 +558,9 @@
 	/*
 	 * Drop the lock reference and switch the owner.  This will result
 	 * in an atomic operation like td_lock is only accessed by curthread
-	 * and lk_lockholder only needs one write.
+	 * and lk_lockholder only needs one write.  Note also that the lock
+	 * owner can be alredy KERNPROC, so in that case just skip the
+	 * decrement.
 	 */
 	if (lkp->lk_lockholder == td)
 		td->td_locks--;