Index: kern_racct.c
===================================================================
diff --git a/head/sys/kern/kern_racct.c b/head/sys/kern/kern_racct.c
--- a/head/sys/kern/kern_racct.c	(revision 240705)
+++ b/head/sys/kern/kern_racct.c	(working copy)
@@ -607,7 +607,9 @@
 	/*
 	 * We don't need to calculate rux, proc_reap() has already done this.
 	 */
+	PROC_SLOCK(p);
 	runtime = cputick2usec(p->p_rux.rux_runtime);
+	PROC_SUNLOCK(p);
 #ifdef notyet
 	KASSERT(runtime >= p->p_prev_runtime, ("runtime < p_prev_runtime"));
 #else