diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -1694,8 +1694,10 @@
 				thread_unlock(td);
 		}
 	}
-	KASSERT(mode != SINGLE_BOUNDARY || p->p_boundary_count == 0,
-	    ("inconsistent boundary count %d", p->p_boundary_count));
+	KASSERT(mode != SINGLE_BOUNDARY || P_SHOULDSTOP(p) ||
+	    p->p_boundary_count == 0,
+	    ("pid %d proc %p flags %#x inconsistent boundary count %d",
+	    p->p_pid, p, p->p_flag, p->p_boundary_count));
 	PROC_SUNLOCK(p);
 	wakeup(&p->p_flag);
 }