linux-kernel - [PATCH 5.4 028/102] net/mlx5e: Fix free peer

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Message-Id: <20200124092810.443854574@linuxfoundation.org>
Date:   Fri, 24 Jan 2020 10:30:29 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Roi Dayan <roid@...lanox.com>,
        Eli Britstein <elibr@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>
Subject: [PATCH 5.4 028/102] net/mlx5e: Fix free peer_flow when refcount is 0

From: Roi Dayan <roid@...lanox.com>

commit eb252c3a24fc5856fa62140c2f8269ddce6ce4e5 upstream.

It could be neigh update flow took a refcount on peer flow so
sometimes we cannot release peer flow even if parent flow is
being freed now.

Fixes: 5a7e5bcb663d ("net/mlx5e: Extend tc flow struct with reference counter")
Signed-off-by: Roi Dayan <roid@...lanox.com>
Reviewed-by: Eli Britstein <elibr@...lanox.com>
Signed-off-by: Saeed Mahameed <saeedm@...lanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -1615,8 +1615,11 @@ static void __mlx5e_tc_del_fdb_peer_flow
 
 	flow_flag_clear(flow, DUP);
 
-	mlx5e_tc_del_fdb_flow(flow->peer_flow->priv, flow->peer_flow);
-	kfree(flow->peer_flow);
+	if (refcount_dec_and_test(&flow->peer_flow->refcnt)) {
+		mlx5e_tc_del_fdb_flow(flow->peer_flow->priv, flow->peer_flow);
+		kfree(flow->peer_flow);
+	}
+
 	flow->peer_flow = NULL;
 }