From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B71B4C43381 for ; Sat, 9 Mar 2019 07:21:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8304D20868 for ; Sat, 9 Mar 2019 07:21:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726758AbfCIHVB (ORCPT ); Sat, 9 Mar 2019 02:21:01 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:44184 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725787AbfCIHVB (ORCPT ); Sat, 9 Mar 2019 02:21:01 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 9090F14BED540; Fri, 8 Mar 2019 23:20:58 -0800 (PST) Date: Fri, 08 Mar 2019 23:20:57 -0800 (PST) Message-Id: <20190308.232057.1297154950610356905.davem@davemloft.net> To: natechancellor@gmail.com Cc: peppe.cavallaro@st.com, alexandre.torgue@st.com, joabreu@synopsys.com, mcoquelin.stm32@gmail.com, netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, ndesaulniers@google.com Subject: Re: [PATCH] net: stmmac: Avoid one more sometimes uninitialized Clang warning From: David Miller In-Reply-To: <20190308040239.9400-1-natechancellor@gmail.com> References: <20190307162101.29204-1-natechancellor@gmail.com> <20190308040239.9400-1-natechancellor@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.1 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]); Fri, 08 Mar 2019 23:20:59 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nathan Chancellor Date: Thu, 7 Mar 2019 21:02:39 -0700 > When building with -Wsometimes-uninitialized, Clang warns: > > drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c:111:2: error: variable > 'ns' is used uninitialized whenever 'if' condition is false > [-Werror,-Wsometimes-uninitialized] > drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c:111:2: error: variable > 'ns' is used uninitialized whenever '&&' condition is false > [-Werror,-Wsometimes-uninitialized] > > Clang is concerned with the use of stmmac_do_void_callback (which > stmmac_get_systime wraps), as it may fail to initialize these values if > the if condition was ever false (meaning the callback doesn't exist). > It's not wrong because the callback is what initializes ns. While it's > unlikely that the callback is going to disappear at some point and make > that condition false, we can easily avoid this warning by zero > initializing the variable. > > Link: https://github.com/ClangBuiltLinux/linux/issues/384 > Fixes: df103170854e ("net: stmmac: Avoid sometimes uninitialized Clang warnings") > Suggested-by: Nick Desaulniers > Signed-off-by: Nathan Chancellor Applied, thanks Nathan.