diff --git a/zfs/lib/libzpool/dmu_tx.c b/zfs/lib/libzpool/dmu_tx.c
index 6a28a19243..93eb58851c 100644
--- a/zfs/lib/libzpool/dmu_tx.c
+++ b/zfs/lib/libzpool/dmu_tx.c
@@ -1025,7 +1025,7 @@ dmu_tx_abort(dmu_tx_t *tx)
 			dnode_rele(dn, tx);
 	}
 
-	while (dcb = list_head(&tx->tx_callbacks)) {
+	while ((dcb = list_head(&tx->tx_callbacks))) {
 		list_remove(&tx->tx_callbacks, dcb);
 
 		/*