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From:   Peilin Ye <yepeilin.cs@gmail.com>
To:     Eric Dumazet <edumazet@google.com>,
        "David S. Miller" <davem@davemloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     Peilin Ye <peilin.ye@bytedance.com>,
        Cong Wang <cong.wang@bytedance.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Peilin Ye <yepeilin.cs@gmail.com>
Subject: [PATCH net v2] net: Use WARN_ON_ONCE() in {tcp,udp}_read_skb()
Date:   Tue, 13 Sep 2022 11:40:16 -0700
Message-Id: <20220913184016.16095-1-yepeilin.cs@gmail.com>
In-Reply-To: <20220908231523.8977-1-yepeilin.cs@gmail.com>
References: <20220908231523.8977-1-yepeilin.cs@gmail.com>
MIME-Version: 1.0
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From: Peilin Ye <peilin.ye@bytedance.com>

Prevent tcp_read_skb() and udp_read_skb() from flooding the syslog.

Suggested-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
---
change since v1:
  - do the same to udp_read_skb() (Cong Wang)

Cong's tcp_read_skb() fix [1] depends on this patch.

[1] https://lore.kernel.org/netdev/20220912173553.235838-1-xiyou.wangcong@gmail.com/

Thanks,
Peilin Ye

 net/ipv4/tcp.c | 2 +-
 net/ipv4/udp.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 8230be00ecca..9251c99d3cfd 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1766,7 +1766,7 @@ int tcp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
 		return 0;
 
 	__skb_unlink(skb, &sk->sk_receive_queue);
-	WARN_ON(!skb_set_owner_sk_safe(skb, sk));
+	WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk));
 	copied = recv_actor(sk, skb);
 	if (copied >= 0) {
 		seq += copied;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index cd72158e953a..560d9eadeaa5 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1821,7 +1821,7 @@ int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor)
 			continue;
 		}
 
-		WARN_ON(!skb_set_owner_sk_safe(skb, sk));
+		WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk));
 		used = recv_actor(sk, skb);
 		if (used <= 0) {
 			if (!copied)
-- 
2.20.1