Author: Julia Lawall <Julia.Lawall@lip6.fr> The calls to pci_iounmap are in the wrong order, as compared to the associated calls to pci_iomap. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // @@ expression e,x; statement S,S1; int ret; @@ e = pci_iomap(x,…) … when != pci_iounmap(x,e) if () S …