| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.9 142/255] net/mlx5e: Fix incorrect access of RCU-protected xdp_prog | Date | Tue, 17 Nov 2020 14:04:42 +0100 |
| |
From: Maxim Mikityanskiy <maximmi@mellanox.com>
[ Upstream commit 1a50cf9a67ff2241c2949d30bc11c8dd4280eef8 ]
rq->xdp_prog is RCU-protected and should be accessed only with rcu_access_pointer for the NULL check in mlx5e_poll_rx_cq.
rq->xdp_prog may change on the fly only from one non-NULL value to another non-NULL value, so the checks in mlx5e_xdp_handle and mlx5e_poll_rx_cq will have the same result during one NAPI cycle, meaning that no additional synchronization is needed.
Fixes: fe45386a2082 ("net/mlx5e: Use RCU to protect rq->xdp_prog") Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Signed-off-by: Saeed Mahameed <saeedm@nvidia.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c index 64c8ac5eabf6a..a0a4398408b85 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -1566,7 +1566,7 @@ int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget) } while ((++work_done < budget) && (cqe = mlx5_cqwq_get_cqe(cqwq))); out: - if (rq->xdp_prog) + if (rcu_access_pointer(rq->xdp_prog)) mlx5e_xdp_rx_poll_complete(rq); mlx5_cqwq_update_db_record(cqwq); -- 2.27.0
|