From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751368AbdCZDGx (ORCPT ); Sat, 25 Mar 2017 23:06:53 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:60008 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751258AbdCZDGw (ORCPT ); Sat, 25 Mar 2017 23:06:52 -0400 Date: Sat, 25 Mar 2017 20:05:53 -0700 (PDT) Message-Id: <20170325.200553.661929780985796313.davem@davemloft.net> To: arnd@arndb.de Cc: dledford@redhat.com, oulijun@huawei.com, xavier.huwei@huawei.com, huangdaode@hisilicon.com, yankejian@huawei.com, xieqianqian@huawei.com, weiyongjun1@huawei.com, yisen.zhuang@huawei.com, salil.mehta@huawei.com, sean.hefty@intel.com, hal.rosenstock@gmail.com, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [RESEND PATCH 2/3] net: hns: avoid gcc-7.0.1 warning for uninitialized data From: David Miller In-Reply-To: <20170324220250.2193128-4-arnd@arndb.de> References: <20170324220250.2193128-1-arnd@arndb.de> <20170324220250.2193128-4-arnd@arndb.de> X-Mailer: Mew version 6.7 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sat, 25 Mar 2017 20:05:54 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arnd Bergmann Date: Fri, 24 Mar 2017 23:02:50 +0100 > hns_dsaf_set_mac_key() calls dsaf_set_field() on an uninitialized field, > which will then change only a few of its bits, causing a warning with > the latest gcc: > > hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_set_mac_uc_entry': > hisilicon/hns/hns_dsaf_reg.h:1046:12: error: 'mac_key.low.bits.port_vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized] > (origin) &= (~(mask)); \ > ^~ > hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_set_mac_mc_entry': > hisilicon/hns/hns_dsaf_reg.h:1046:12: error: 'mac_key.low.bits.port_vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized] > hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_add_mac_mc_port': > hisilicon/hns/hns_dsaf_reg.h:1046:12: error: 'mac_key.low.bits.port_vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized] > hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_del_mac_entry': > hisilicon/hns/hns_dsaf_reg.h:1046:12: error: 'mac_key.low.bits.port_vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized] > hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_rm_mac_addr': > hisilicon/hns/hns_dsaf_reg.h:1046:12: error: 'mac_key.low.bits.port_vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized] > hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_del_mac_mc_port': > hisilicon/hns/hns_dsaf_reg.h:1046:12: error: 'mac_key.low.bits.port_vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized] > hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_get_mac_uc_entry': > hisilicon/hns/hns_dsaf_reg.h:1046:12: error: 'mac_key.low.bits.port_vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized] > hisilicon/hns/hns_dsaf_main.c: In function 'hns_dsaf_get_mac_mc_entry': > hisilicon/hns/hns_dsaf_reg.h:1046:12: error: 'mac_key.low.bits.port_vlan' may be used uninitialized in this function [-Werror=maybe-uninitialized] > > The code is actually correct since we always set all 16 bits of the > port_vlan field, but gcc correctly points out that the first > access does contain uninitialized data. > > This initializes the field to zero first before setting the > individual bits. > > Fixes: 5483bfcb169c ("net: hns: modify tcam table and set mac key") > Signed-off-by: Arnd Bergmann Applied.