Author: Julien Brunel <brunel@diku.dk> In case of error, the function p9_client_walk returns an ERR pointer, but never returns a NULL pointer. So a NULL test that comes after an IS_ERR test should be deleted. The semantic match that finds this problem is as follows: (http://www.emn.fr/x-info/coccinelle/) // @match_bad_null_test@ expression x, E; statement S1,S2; @@ x = …