diff --git a/src/include/binary_hist.h b/src/include/binary_hist.h
index fc277ab64..0c10e85f1 100644
--- a/src/include/binary_hist.h
+++ b/src/include/binary_hist.h
@@ -42,6 +42,9 @@ binary_hist_init(struct binary_hist *bh, int start_bit, int num_buckets)
 static inline int
 binary_hist_size(const struct binary_hist *bh)
 {
+    if (!bh)
+	return -EINVAL;
+
     return bh->bh_num_buckets;
 }
 
diff --git a/test/raft-reference-client.c b/test/raft-reference-client.c
index 4aeb2005f..9fc9a8142 100644
--- a/test/raft-reference-client.c
+++ b/test/raft-reference-client.c
@@ -1105,8 +1105,14 @@ raft_client_test_instance_hist_lreg_multi_facet_handler(
     struct raft_instance_hist_stats *rihs,
     struct lreg_value *lv)
 {
-    if (!lv ||
-        lv->lrv_value_idx_in >= binary_hist_size(&rihs->rihs_bh))
+    if (!lv || !rihs)
+	return -EINVAL;
+
+    int hsz = binary_hist_size(&rihs->rihs_bh);
+    if (hsz < 0)
+	return hsz;
+
+    if (lv->lrv_value_idx_in >= (uint32_t)hsz)
         return -EINVAL;
 
     else if (op == LREG_NODE_CB_OP_WRITE_VAL)