Author: Julia Lawall <julia@diku.dk> If ibss_wlan is NULL, it is not correct to memcpy into its field. The semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // @r@ expression E, E1; identifier f; statement S1,S2,S3; @@ if (E == NULL) { … when != if (E == NULL || …) S1 else S2 …