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From:   Ma Ke <make_ruc2021@163.com>
To:     jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
        davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Ma Ke <make_ruc2021@163.com>
Subject: [PATCH] net: sched: qfq: dont intepret cls results when asked to drop
Date:   Fri, 15 Sep 2023 22:23:55 +0800
Message-Id: <20230915142355.3411527-1-make_ruc2021@163.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

If asked to drop a packet via TC_ACT_SHOT it is unsafe to
assume that res.class contains a valid pointer.

Signed-off-by: Ma Ke <make_ruc2021@163.com>
---
 net/sched/sch_qfq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
index 546c10adcacd..91c323eff012 100644
--- a/net/sched/sch_qfq.c
+++ b/net/sched/sch_qfq.c
@@ -696,6 +696,8 @@ static struct qfq_class *qfq_classify(struct sk_buff *skb, struct Qdisc *sch,
 	fl = rcu_dereference_bh(q->filter_list);
 	result = tcf_classify(skb, NULL, fl, &res, false);
 	if (result >= 0) {
+		if (result == TC_ACT_SHOT)
+			return NULL;
 #ifdef CONFIG_NET_CLS_ACT
 		switch (result) {
 		case TC_ACT_QUEUED:
@@ -703,8 +705,6 @@ static struct qfq_class *qfq_classify(struct sk_buff *skb, struct Qdisc *sch,
 		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 			fallthrough;
-		case TC_ACT_SHOT:
-			return NULL;
 		}
 #endif
 		cl = (struct qfq_class *)res.class;
-- 
2.37.2