diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 297e19d..9aeeb52 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -105,6 +105,9 @@
 	struct scatter_walk walk;
 	unsigned int offset = 0;
 
+	if (!nbytes)
+		return;
+
 	for (;;) {
 		scatterwalk_start(&walk, sg);