diff --git a/nbd.c b/nbd.c
index fcf0339292..c7d63d3487 100644
--- a/nbd.c
+++ b/nbd.c
@@ -388,7 +388,7 @@ int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, o
 	}
 
 	if (len > sizeof(data)) {
-		LOG("len (%u) is larger than max len (%lu)",
+		LOG("len (%u) is larger than max len (%u)",
 		    len, sizeof(data));
 		errno = EINVAL;
 		return -1;