Author: Julia Lawall <julia@diku.dk> Since card must already be non-NULL, it seems that what was intended was to test the result of kmalloc. The semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // @@ expression E,E1; identifier f,fld,fld1; statement S1,S2; @@ E->fld = f(…); … when != E = E1 when != E->fld1 …