[patch net] net: sched: fix p_filter_chain check in tcf_chain_flush

From: Jiri Pirko <redacted>

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 <redacted>
---
 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 ebeeb87..eef6b07 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c

@@ -190,7 +190,7 @@ 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);

-- 
2.9.3

On Fri, Aug 18, 2017 at 1:10 AM, Jiri Pirko [off-list ref] wrote:

From: Jiri Pirko <redacted>

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 <redacted>

Acked-by: Cong Wang <redacted>

From: Jiri Pirko <jiri@resnulli.us>
Date: Fri, 18 Aug 2017 10:10:43 +0200

From: Jiri Pirko <redacted>

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 <redacted>

Applied, thanks Jiri.