Author: Julien Brunel <brunel@diku.dk> In case of error, the function ucma_alloc_multicast() returns a NULL pointer, but never returns an ERR pointer. So after a call to this function, an IS_ERR test should be replaced by a NULL test. The semantic match that finds this problem is as follows: (http://www.emn.fr/x-info/coccinelle/) // @match bad_is_err_test@ expression x, E; …