netdev - [PATCH net] amt: do not use overwrapped cb area

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Message-Id: <20240107144241.4169520-1-ap420073@gmail.com>
Date: Sun,  7 Jan 2024 14:42:41 +0000
From: Taehee Yoo <ap420073@...il.com>
To: davem@...emloft.net,
	kuba@...nel.org,
	pabeni@...hat.com,
	edumazet@...gle.com,
	netdev@...r.kernel.org
Cc: ap420073@...il.com,
	paulb@...dia.com,
	jhs@...atatu.com
Subject: [PATCH net] amt: do not use overwrapped cb area

amt driver uses skb->cb for storing tunnel information.
This job is worked before TC layer and then amt driver load tunnel info
from skb->cb after TC layer.
So, its cb area should not be overwrapped with CB area used by TC.
In order to not use cb area used by TC, it skips the biggest cb
structure used by TC, which was qdisc_skb_cb.
But it's not anymore.
Currently, biggest structure of TC's CB is tc_skb_cb.
So, it should skip size of tc_skb_cb instead of qdisc_skb_cb.

Fixes: ec624fe740b4 ("net/sched: Extend qdisc control block with tc control block")
Signed-off-by: Taehee Yoo <ap420073@...il.com>
---
 drivers/net/amt.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/amt.c b/drivers/net/amt.c
index 53415e83821c..68e79b1272f6 100644
--- a/drivers/net/amt.c
+++ b/drivers/net/amt.c
@@ -11,7 +11,7 @@
 #include <linux/net.h>
 #include <linux/igmp.h>
 #include <linux/workqueue.h>
-#include <net/sch_generic.h>
+#include <net/pkt_sched.h>
 #include <net/net_namespace.h>
 #include <net/ip.h>
 #include <net/udp.h>
@@ -80,11 +80,11 @@ static struct mld2_grec mldv2_zero_grec;
 
 static struct amt_skb_cb *amt_skb_cb(struct sk_buff *skb)
 {
-	BUILD_BUG_ON(sizeof(struct amt_skb_cb) + sizeof(struct qdisc_skb_cb) >
+	BUILD_BUG_ON(sizeof(struct amt_skb_cb) + sizeof(struct tc_skb_cb) >
 		     sizeof_field(struct sk_buff, cb));
 
 	return (struct amt_skb_cb *)((void *)skb->cb +
-		sizeof(struct qdisc_skb_cb));
+		sizeof(struct tc_skb_cb));
 }
 
 static void __amt_source_gc_work(void)
-- 
2.34.1