diff --git a/include/ck_ring.h b/include/ck_ring.h
index 317bf76..4a7a31f 100644
--- a/include/ck_ring.h
+++ b/include/ck_ring.h
@@ -67,7 +67,7 @@
 										\
 		c = ck_pr_load_uint(&ring->c_head);				\
 		p = ck_pr_load_uint(&ring->p_tail);				\
-		return (p - c);							\
+		return (p - c) & ring->mask;					\
 	}									\
 	CK_CC_INLINE static unsigned int					\
 	ck_ring_capacity_##name(struct ck_ring_##name *ring)			\
@@ -148,7 +148,7 @@ ck_ring_size(struct ck_ring *ring)
 
 	c = ck_pr_load_uint(&ring->c_head);
 	p = ck_pr_load_uint(&ring->p_tail);
-	return (p - c);
+	return (p - c) & ring->mask;
 }
 
 CK_CC_INLINE static unsigned int
diff --git a/regressions/ck_ring/validate/ck_ring_spsc.c b/regressions/ck_ring/validate/ck_ring_spsc.c
index d6e786c..238a770 100644
--- a/regressions/ck_ring/validate/ck_ring_spsc.c
+++ b/regressions/ck_ring/validate/ck_ring_spsc.c
@@ -73,7 +73,7 @@ test(void *c)
 		assert(entries != NULL);
 
 		if (ck_ring_size(ring) != 0) {
-			fprintf(stderr, "Less entries than expected: %u > 0\n",
+			fprintf(stderr, "More entries than expected: %u > 0\n",
 				ck_ring_size(ring));
 			exit(EXIT_FAILURE);
 		}
@@ -83,6 +83,7 @@ test(void *c)
 			entries[i].tid = 0;
 
 			r = ck_ring_enqueue_spsc(ring, entries + i);
+			assert(r != false);
 		}
 
 		if (ck_ring_size(ring) != (unsigned int)size) {