From patchwork Sun May 15 07:27:24 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Shamir Rabinovitch X-Patchwork-Id: 9096291 Return-Path: X-Original-To: patchwork-linux-rdma@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 135F69F1C1 for ; Sun, 15 May 2016 07:28:08 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2CD4520272 for ; Sun, 15 May 2016 07:28:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2989D2026F for ; Sun, 15 May 2016 07:28:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752504AbcEOH2C (ORCPT ); Sun, 15 May 2016 03:28:02 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:45454 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752082AbcEOH2C (ORCPT ); Sun, 15 May 2016 03:28:02 -0400 Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id u4F7RmPc026399 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sun, 15 May 2016 07:27:49 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.13.8/8.13.8) with ESMTP id u4F7Rl5B018200 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sun, 15 May 2016 07:27:48 GMT Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id u4F7Rk93028947; Sun, 15 May 2016 07:27:47 GMT Received: from shamir-net-srv.us.oracle.com (/10.211.3.248) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 15 May 2016 00:27:46 -0700 From: shamir.rabinovitch@oracle.com To: linux-rdma@vger.kernel.org Cc: yishaih@mellanox.com, dledford@redhat.com, sean.hefty@intel.com, hal.rosenstock@gmail.com, shamir.rabinovitch@oracle.com Subject: [PATCH v1 1/1] mlx4/mad: unalign access in send_reply_to_slave Date: Sun, 15 May 2016 03:27:24 -0400 Message-Id: <1463297244-3837-1-git-send-email-shamir.rabinovitch@oracle.com> X-Mailer: git-send-email 1.7.1 X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Spam-Status: No, score=-8.3 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Shamir Rabinovitch The problem is that the function 'send_reply_to_slave' get the 'req_sa_mad' as pointer whose address can be unaligned to 8 bytes. In this case the compiler cannot know in advance what will be the alignment of the 'data' field. Sowmini Varadhan pointed to this reply from Dave Miller that say that memcpy should not be used to solve alignment issues: https://lkml.org/lkml/2015/10/21/352 The reason why memcpy works here is because we memcpy someting that is bigger then 8 bytes and so the compiler cannot optimize this to 'ldx' instruction. Signed-off-by: Shamir Rabinovitch --- drivers/infiniband/hw/mlx4/mcg.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/drivers/infiniband/hw/mlx4/mcg.c b/drivers/infiniband/hw/mlx4/mcg.c index 99451d8..180f76b 100644 --- a/drivers/infiniband/hw/mlx4/mcg.c +++ b/drivers/infiniband/hw/mlx4/mcg.c @@ -319,8 +319,9 @@ static int send_reply_to_slave(int slave, struct mcast_group *group, struct ib_sa_mad *req_sa_mad, u16 status) { struct ib_sa_mad mad; + struct ib_sa_mcmember_data req_data; struct ib_sa_mcmember_data *sa_data = (struct ib_sa_mcmember_data *)&mad.data; - struct ib_sa_mcmember_data *req_sa_data = (struct ib_sa_mcmember_data *)&req_sa_mad->data; + struct ib_sa_mcmember_data *req_sa_data = &req_data; int ret; memset(&mad, 0, sizeof mad); @@ -343,6 +344,11 @@ static int send_reply_to_slave(int slave, struct mcast_group *group, /* reconstruct VF's requested join_state and port_gid */ sa_data->scope_join_state &= 0xf0; sa_data->scope_join_state |= (group->func[slave].join_state & 0x0f); + BUILD_BUG_ON(sizeof(req_sa_mad->data) < sizeof(req_data)); + /* req_sa_mad is packed structure whose start address is not + * aligned to 8 + */ + memcpy(&req_data, &req_sa_mad->data, sizeof(req_data)); memcpy(&sa_data->port_gid, &req_sa_data->port_gid, sizeof req_sa_data->port_gid); ret = send_mad_to_slave(slave, group->demux, (struct ib_mad *)&mad);