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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Xin Long <lucien.xin@gmail.com>,
        Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 119/243] sctp: increase sk_wmem_alloc when head->truesize is increased
Date:   Wed, 11 Dec 2019 16:04:41 +0100
Message-Id: <20191211150347.164875650@linuxfoundation.org>
In-Reply-To: <20191211150339.185439726@linuxfoundation.org>
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From: Xin Long <lucien.xin@gmail.com>

[ Upstream commit 0d32f17717e65e76cbdb248374dd162acdfe2fff ]

I changed to count sk_wmem_alloc by skb truesize instead of 1 to
fix the sk_wmem_alloc leak caused by later truesize's change in
xfrm in Commit 02968ccf0125 ("sctp: count sk_wmem_alloc by skb
truesize in sctp_packet_transmit").

But I should have also increased sk_wmem_alloc when head->truesize
is increased in sctp_packet_gso_append() as xfrm does. Otherwise,
sctp gso packet will cause sk_wmem_alloc underflow.

Fixes: 02968ccf0125 ("sctp: count sk_wmem_alloc by skb truesize in sctp_packet_transmit")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sctp/output.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/sctp/output.c b/net/sctp/output.c
index b0e74a3e77ec5..025f48e14a91f 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -410,6 +410,7 @@ static void sctp_packet_gso_append(struct sk_buff *head, struct sk_buff *skb)
 	head->truesize += skb->truesize;
 	head->data_len += skb->len;
 	head->len += skb->len;
+	refcount_add(skb->truesize, &head->sk->sk_wmem_alloc);
 
 	__skb_header_release(skb);
 }
-- 
2.20.1