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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, Jon Maloy <jmaloy@redhat.com>,
        Tung Nguyen <tung.q.nguyen@dektech.com.au>,
        Hoang Le <hoang.h.le@dektech.com.au>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.4 075/177] Revert "net:tipc: Fix a double free in tipc_sk_mcast_rcv"
Date:   Mon, 31 May 2021 15:13:52 +0200
Message-Id: <20210531130650.488352959@linuxfoundation.org>
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From: Hoang Le <hoang.h.le@dektech.com.au>

commit 75016891357a628d2b8acc09e2b9b2576c18d318 upstream.

This reverts commit 6bf24dc0cc0cc43b29ba344b66d78590e687e046.
Above fix is not correct and caused memory leak issue.

Fixes: 6bf24dc0cc0c ("net:tipc: Fix a double free in tipc_sk_mcast_rcv")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Acked-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/tipc/socket.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1210,7 +1210,10 @@ void tipc_sk_mcast_rcv(struct net *net,
 		spin_lock_bh(&inputq->lock);
 		if (skb_peek(arrvq) == skb) {
 			skb_queue_splice_tail_init(&tmpq, inputq);
-			__skb_dequeue(arrvq);
+			/* Decrease the skb's refcnt as increasing in the
+			 * function tipc_skb_peek
+			 */
+			kfree_skb(__skb_dequeue(arrvq));
 		}
 		spin_unlock_bh(&inputq->lock);
 		__skb_queue_purge(&tmpq);