Author: Julia Lawall <julia@diku.dk> Pci_get_slot calls pci_dev_get, so pci_dev_put is needed before leaving the function in the case where pci_get_slot is locally used. The semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // @@ local idexpression x; expression e; @@ *x = pci_get_slot(…) … when != true x == NULL when != pci_dev_put(x) …