[PATCH net] 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.
Initialize .miss_cookie_node pointer to 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 | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 35785a36c80298..8bc5b9d6a2916e 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -3224,8 +3224,12 @@ int tcf_exts_init_ex(struct tcf_exts *exts, struct net *net, int action,
 	exts->action = action;
 	exts->police = police;
 
-	if (!use_action_miss)
+	if (!use_action_miss) {
+#ifdef CONFIG_NET_CLS_ACT
+		exts->miss_cookie_node = NULL;
+#endif
 		return 0;
+	}
 
 	err = tcf_exts_miss_cookie_base_alloc(exts, tp, handle);
 	if (err)
-- 
2.39.2