Index: sys/kern/kern_ktrace.c
===================================================================
--- sys/kern/kern_ktrace.c
+++ sys/kern/kern_ktrace.c
@@ -1224,37 +1224,58 @@
 	return (1);
 }
 
+static struct proc *
+ktr_next_descendant(struct proc *top, struct proc *p)
+{
+	struct proc *n;
+
+	sx_assert(&proctree_lock, SX_LOCKED);
+
+	LIST_FOREACH(n, &p->p_children, p_sibling) {
+		if (n->p_pptr == proc_realparent(n))
+			return (n);
+	}
+
+	for (; p != top; p = p->p_pptr) {
+		n = LIST_NEXT(p, p_sibling);
+		if (n == NULL)
+			continue;
+
+		KASSERT(p->p_pptr == proc_realparent(p),
+		    ("%s: reparented proc %p", __func__, p));
+		LIST_FOREACH_FROM(n, &p->p_pptr->p_children, p_sibling) {
+			if (n->p_pptr == proc_realparent(n))
+				return (n);
+		}
+	}
+	return (NULL);
+}
+
 static int
 ktrsetchildren(struct thread *td, struct proc *top, int ops, int facs,
     struct ktr_io_params *new_kiop)
 {
-	struct proc *p;
-	int ret = 0;
+	struct proc *o, *p;
+	int ret;
 
-	p = top;
-	PROC_LOCK_ASSERT(p, MA_OWNED);
 	sx_assert(&proctree_lock, SX_LOCKED);
-	for (;;) {
+	PROC_LOCK_ASSERT(top, MA_OWNED);
+
+	ret = 0;
+	for (p = top;;) {
 		ret |= ktrops(td, p, ops, facs, new_kiop);
-		/*
-		 * If this process has children, descend to them next,
-		 * otherwise do any siblings, and if done with this level,
-		 * follow back up the tree (but not past top).
-		 */
-		if (!LIST_EMPTY(&p->p_children))
-			p = LIST_FIRST(&p->p_children);
-		else for (;;) {
-			if (p == top)
-				return (ret);
-			if (LIST_NEXT(p, p_sibling)) {
-				p = LIST_NEXT(p, p_sibling);
-				break;
-			}
-			p = p->p_pptr;
+
+		LIST_FOREACH(o, &p->p_orphans, p_orphan) {
+			PROC_LOCK(o);
+			ret |= ktrops(td, o, ops, facs, new_kiop);
 		}
+
+		p = ktr_next_descendant(top, p);
+		if (p == NULL)
+			break;
 		PROC_LOCK(p);
 	}
-	/*NOTREACHED*/
+	return (ret);
 }
 
 static void