Author: Julia Lawall <julia@diku.dk> Btrfs_alloc_path should be matched with btrfs_free_path in error-handling code. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // @r exists@ local idexpression struct btrfs_path * x; expression ra,rb; position p1,p2; @@ x = btrfs_alloc_path@p1(…) … when != btrfs_free_path(x,…) when != if (…) { … …