diff --git a/sys/kern/kern_jail.c b/sys/kern/kern_jail.c
--- a/sys/kern/kern_jail.c
+++ b/sys/kern/kern_jail.c
@@ -777,19 +777,19 @@
 
 /*
  * Restrict a prison's IP address list with its parent's, possibly replacing
- * it.  Return true if the replacement buffer was used (or should redo).
+ * it.  Return true if succeed, otherwise should redo.
  * kern_jail_set() helper.
  */
 static bool
 prison_ip_restrict(struct prison *pr, const pr_family_t af,
-    struct prison_ip *new)
+    struct prison_ip **newp)
 {
 	const struct prison_ip *ppip = pr->pr_parent->pr_addrs[af];
 	const struct prison_ip *pip = pr->pr_addrs[af];
 	int (*const cmp)(const void *, const void *) = pr_families[af].cmp;
 	const size_t size = pr_families[af].size;
+	struct prison_ip *new = newp != NULL ? *newp : NULL;
 	uint32_t ips;
-	bool alloced, used;
 
 	mtx_assert(&pr->pr_mtx, MA_OWNED);
 
@@ -803,22 +803,21 @@
 	if (ppip == NULL) {
 		if (pip != NULL)
 			prison_ip_set(pr, af, NULL);
-		return (false);
+		return (true);
 	}
 
 	if (!(pr->pr_flags & pr_families[af].ip_flag)) {
 		if (new == NULL) {
 			new = prison_ip_alloc(af, ppip->ips, M_NOWAIT);
 			if (new == NULL)
-				return (true); /* redo */
-			used = false;
-		} else
-			used = true;
+				return (false); /* Redo */
+		}
 		/* This has no user settings, so just copy the parent's list. */
 		MPASS(new->ips == ppip->ips);
 		bcopy(ppip + 1, new + 1, ppip->ips * size);
 		prison_ip_set(pr, af, new);
-		return (used);
+		if (newp != NULL)
+			*newp = NULL; /* Used */
 	} else if (pip != NULL) {
 		/* Remove addresses that aren't in the parent. */
 		int i;
@@ -826,16 +825,10 @@
 		i = 0; /* index in pip */
 		ips = 0; /* index in new */
 
-		used = true;
 		if (new == NULL) {
 			new = prison_ip_alloc(af, pip->ips, M_NOWAIT);
 			if (new == NULL)
-				return (true); /* redo */
-			used = false;
-			alloced = true;
-		} else {
-			used = true;
-			alloced = false;
+				return (false); /* Redo */
 		}
 
 		for (int pi = 0; pi < ppip->ips; pi++)
@@ -873,10 +866,9 @@
 			}
 		}
 		if (ips == 0) {
-			if (alloced)
+			if (newp == NULL || *newp == NULL)
 				prison_ip_free(new);
 			new = NULL;
-			used = false;
 		} else {
 			/* Shrink to real size */
 			KASSERT((new->ips >= ips),
@@ -884,9 +876,10 @@
 			new->ips = ips;
 		}
 		prison_ip_set(pr, af, new);
-		return (used);
+		if (newp != NULL)
+			*newp = NULL; /* Used */
 	}
-	return (false);
+	return (true);
 }
 
 /*
@@ -984,10 +977,12 @@
 	int jid, jsys, len, level;
 	int childmax, osreldt, rsnum, slevel;
 #ifdef INET
-	int ip4s, redo_ip4;
+	int ip4s;
+	bool redo_ip4;
 #endif
 #ifdef INET6
-	int ip6s, redo_ip6;
+	int ip6s;
+	bool redo_ip6;
 #endif
 	uint64_t pr_allow, ch_allow, pr_flags, ch_flags;
 	uint64_t pr_allow_diff;
@@ -1864,7 +1859,7 @@
 
 	/* Set the parameters of the prison. */
 #ifdef INET
-	redo_ip4 = 0;
+	redo_ip4 = false;
 	if (pr_flags & PR_IP4_USER) {
 		pr->pr_flags |= PR_IP4;
 		prison_ip_set(pr, PR_INET, ip4);
@@ -1876,15 +1871,15 @@
 				continue;
 			}
 #endif
-			if (prison_ip_restrict(tpr, PR_INET, NULL)) {
-				redo_ip4 = 1;
+			if (!prison_ip_restrict(tpr, PR_INET, NULL)) {
+				redo_ip4 = true;
 				descend = 0;
 			}
 		}
 	}
 #endif
 #ifdef INET6
-	redo_ip6 = 0;
+	redo_ip6 = false;
 	if (pr_flags & PR_IP6_USER) {
 		pr->pr_flags |= PR_IP6;
 		prison_ip_set(pr, PR_INET6, ip6);
@@ -1896,8 +1891,8 @@
 				continue;
 			}
 #endif
-			if (prison_ip_restrict(tpr, PR_INET6, NULL)) {
-				redo_ip6 = 1;
+			if (!prison_ip_restrict(tpr, PR_INET6, NULL)) {
+				redo_ip6 = true;
 				descend = 0;
 			}
 		}
@@ -2041,9 +2036,10 @@
 #ifdef INET
 	while (redo_ip4) {
 		ip4s = pr->pr_addrs[PR_INET]->ips;
+		MPASS(ip4 == NULL);
 		ip4 = prison_ip_alloc(PR_INET, ip4s, M_WAITOK);
 		mtx_lock(&pr->pr_mtx);
-		redo_ip4 = 0;
+		redo_ip4 = false;
 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
 #ifdef VIMAGE
 			if (tpr->pr_flags & PR_VNET) {
@@ -2051,12 +2047,7 @@
 				continue;
 			}
 #endif
-			if (prison_ip_restrict(tpr, PR_INET, ip4)) {
-				if (ip4 != NULL)
-					ip4 = NULL;
-				else
-					redo_ip4 = 1;
-			}
+			redo_ip4 = !prison_ip_restrict(tpr, PR_INET, &ip4);
 		}
 		mtx_unlock(&pr->pr_mtx);
 	}
@@ -2064,9 +2055,10 @@
 #ifdef INET6
 	while (redo_ip6) {
 		ip6s = pr->pr_addrs[PR_INET6]->ips;
+		MPASS(ip6 == NULL);
 		ip6 = prison_ip_alloc(PR_INET6, ip6s, M_WAITOK);
 		mtx_lock(&pr->pr_mtx);
-		redo_ip6 = 0;
+		redo_ip6 = false;
 		FOREACH_PRISON_DESCENDANT_LOCKED(pr, tpr, descend) {
 #ifdef VIMAGE
 			if (tpr->pr_flags & PR_VNET) {
@@ -2074,12 +2066,7 @@
 				continue;
 			}
 #endif
-			if (prison_ip_restrict(tpr, PR_INET6, ip6)) {
-				if (ip6 != NULL)
-					ip6 = NULL;
-				else
-					redo_ip6 = 1;
-			}
+			redo_ip6 = !prison_ip_restrict(tpr, PR_INET6, &ip6);
 		}
 		mtx_unlock(&pr->pr_mtx);
 	}