Author: Julia Lawall <julia@diku.dk> If port is NULL, then the call to dev_err will dereference a value that is a small offset from NULL. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // @r exists@ expression E,E1; identifier f; statement S1,S2,S3; @@ if ((E == NULL && …) …