From acc8b31665b4cc17b35c4fa445427f7e2f6dc86b Mon Sep 17 00:00:00 2001 From: Jiri Pirko Date: Fri, 18 Aug 2017 10:10:43 +0200 Subject: [PATCH] net: sched: fix p_filter_chain check in tcf_chain_flush The dereference before check is wrong and leads to an oops when p_filter_chain is NULL. The check needs to be done on the pointer to prevent NULL dereference. Fixes: f93e1cdcf42c ("net/sched: fix filter flushing") Signed-off-by: Jiri Pirko Acked-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/cls_api.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 39da0c5801c9..9fd44c221347 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -205,7 +205,7 @@ static void tcf_chain_flush(struct tcf_chain *chain) { struct tcf_proto *tp; - if (*chain->p_filter_chain) + if (chain->p_filter_chain) RCU_INIT_POINTER(*chain->p_filter_chain, NULL); while ((tp = rtnl_dereference(chain->filter_chain)) != NULL) { RCU_INIT_POINTER(chain->filter_chain, tp->next); -- 2.20.1