diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 8d82511aa1bca6c134d8828d6962082160502bba..d83ccb8c982b9d8f8e68eea52de61d1b68c875ba 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -571,7 +571,7 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
 
 		if (gso.hdr_len > len)
 			return -EINVAL;
-		offset += sizeof(pi);
+		offset += sizeof(gso);
 	}
 
 	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {