From patchwork Tue Nov 3 19:18:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Saeed Mahameed X-Patchwork-Id: 1393351 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=nvidia.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=nvidia.com header.i=@nvidia.com header.a=rsa-sha256 header.s=n1 header.b=jtsGutuS; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CQfjS4NWKz9sT6 for ; Wed, 4 Nov 2020 06:19:24 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729675AbgKCTTX (ORCPT ); Tue, 3 Nov 2020 14:19:23 -0500 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:4565 "EHLO hqnvemgate26.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729652AbgKCTTR (ORCPT ); Tue, 3 Nov 2020 14:19:17 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Tue, 03 Nov 2020 11:19:20 -0800 Received: from sx1.mtl.com (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 3 Nov 2020 19:19:06 +0000 From: Saeed Mahameed To: Jakub Kicinski CC: "David S. Miller" , , "Maxim Mikityanskiy" , Tariq Toukan , "Saeed Mahameed" Subject: [net 9/9] net/mlx5e: Fix incorrect access of RCU-protected xdp_prog Date: Tue, 3 Nov 2020 11:18:30 -0800 Message-ID: <20201103191830.60151-10-saeedm@nvidia.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201103191830.60151-1-saeedm@nvidia.com> References: <20201103191830.60151-1-saeedm@nvidia.com> MIME-Version: 1.0 X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1604431160; bh=Me4k3oBtLi1R1bUzXFhth6SnIPa/YVgeeB1Nn0ImP/A=; h=From:To:CC:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding:Content-Type: X-Originating-IP:X-ClientProxiedBy; b=jtsGutuSViqt/TjVdJiuCGlI2kp5oqv0Md4qGYPpsrTuauvUvj1mCPEKO3l+as4tF PghbFhofYYb8sf/zzVv+SRUIT4In8MabwEunYTrWTcUNBLlcMC2ICJ28isaClveNj6 Cg77ZkmnQx0RRKtl2qQYxSls8QNlRX2bCw2ySdebtZKEHzVVH1PYcJDVZW0BVMBd5j M8z7x8o82Uc1waP8J2FksDGXBxWiXfz95qEEFuGTO8R5vojGw7sJgHnIYY0DtV71Cp mbmtkgyHjuAI1ZI7PIc0oLxvJ6V4O55bpNi64BQDL84BjirX6Y6UOAUg5dDAMgMn3a c2jLQ3kg5RpVg== Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Maxim Mikityanskiy 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 Reviewed-by: Tariq Toukan Signed-off-by: Saeed Mahameed --- 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 599f5b5ebc97..6628a0197b4e 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -1584,7 +1584,7 @@ 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);