[PATCH net v2] net/sched: cls_api: Initialize miss_cookie_node when action miss is not used

[Ivan Vecera <ivecera@redhat.com>]

Function tcf_exts_init_ex() sets exts->miss_cookie_node ptr only
when use_action_miss is true so it assumes in other case that
the field is set to NULL by the caller. If not then the field
contains garbage and subsequent tcf_exts_destroy() call results
in a crash.
Ensure that the field .miss_cookie_node pointer is NULL when
use_action_miss parameter is false to avoid this potential scenario.

Fixes: 80cd22c35c90 ("net/sched: cls_api: Support hardware miss to tc action")
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
---
 net/sched/cls_api.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 35785a36c80298..3c3629c9e7b65c 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -3211,6 +3211,7 @@ int tcf_exts_init_ex(struct tcf_exts *exts, struct net *net, int action,
 #ifdef CONFIG_NET_CLS_ACT
 	exts->type = 0;
 	exts->nr_actions = 0;
+	exts->miss_cookie_node = NULL;
 	/* Note: we do not own yet a reference on net.
 	 * This reference might be taken later from tcf_exts_get_net().
 	 */
-- 
2.39.2