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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 BED75C11D00 for ; Fri, 21 Feb 2020 01:38:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 958F824650 for ; Fri, 21 Feb 2020 01:38:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="iIwqxWQ4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729301AbgBUBh7 (ORCPT ); Thu, 20 Feb 2020 20:37:59 -0500 Received: from mail-ot1-f67.google.com ([209.85.210.67]:42759 "EHLO mail-ot1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727790AbgBUBh7 (ORCPT ); Thu, 20 Feb 2020 20:37:59 -0500 Received: by mail-ot1-f67.google.com with SMTP id 66so602520otd.9 for ; Thu, 20 Feb 2020 17:37:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=gwaIL0Zgd1393X/RibdnLwLrFqFzUdQWIreaIHF/WLw=; b=iIwqxWQ4u/9znwKAlwzdzQqJrZzfeBhCG70xvk1hPhL9rd/Z6fFnb9Iu0pJ4qYDHoN jX0C/RNrFadi4Ap+ZsjhHqbLHPVC16W7MigffpaR127jX2O5xx+lgkcMCrbKWS+Lmp2U uzL94HbeKvS/ekYuWJmtC01dANoCZsIjRTC7YTnloxqc/n85nkorruVF2nBPo3B/YBid ARdBz6AWPcm2Sbz0rJ67uVMj9s7YXUA27DyMfJxNKz2My0O62EMICBGOcvRPxKwww0BD HQtRD9aC9EGvyBT4LLB8TUBDgpAl3PnQgW/sbw8HCOnQb7Cn0N0kO7QcuuSaR+Mx2ofc TdoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=gwaIL0Zgd1393X/RibdnLwLrFqFzUdQWIreaIHF/WLw=; b=FJa2iaMD7rUgJ5uJzAmrASeJGJzBG6V7SZmZVFVQum86ulSdD0pwZzYSjwJ0mD90RX Ctt570v6RSMUb9NaSe5/rBU1D1kKb7BVq68yLGf3/EW8Oo4YbcpTs8845VV3jHkuKHKh 5WSX8g1nqiLWr1fnM37E+/SLEfr8qVnfkUkunqH4UshxkS+Wk/7stNWRNU2VKHJsx/dT ddLUTLrV+5cVlIdKSmQF5VzS7SP6Joh7KWIgspPpTQro+u0fac6LApbmtgZ56/SQA8T4 HKntBj6AWObgbdNw+X0JvgiwMTxOpvUQwT3Y60iepGX2uuZkLOjec8PNVfJyJX7gk9iJ 28Bg== X-Gm-Message-State: APjAAAUmGtApb5CslEMK8HqrbthNo6HQTa648gswIQEUHF54mTHMpPkW Yi/A+zsxsdU93drnSfTfIAM= X-Google-Smtp-Source: APXvYqxy9kbr7XHBnZUt1BeLIXoaHOsii1k8aJhci8JkdsdnQNQKC4zJbiBitU6vYTO/HrluDHgCvQ== X-Received: by 2002:a9d:21c5:: with SMTP id s63mr13555844otb.142.1582249078447; Thu, 20 Feb 2020 17:37:58 -0800 (PST) Received: from ubuntu-m2-xlarge-x86 ([2604:1380:4111:8b00::1]) by smtp.gmail.com with ESMTPSA id c10sm460048otl.77.2020.02.20.17.37.57 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 20 Feb 2020 17:37:57 -0800 (PST) Date: Thu, 20 Feb 2020 18:37:56 -0700 From: Nathan Chancellor To: Andrew Morton Cc: Catalin Marinas , linux-mm@kvack.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Nick Desaulniers Subject: Re: [PATCH v2] mm: kmemleak: Use address-of operator on section symbols Message-ID: <20200221013756.GA8323@ubuntu-m2-xlarge-x86> References: <20200220051551.44000-1-natechancellor@gmail.com> <20200220173501.0de88326911e41b15e27b62f@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200220173501.0de88326911e41b15e27b62f@linux-foundation.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 20, 2020 at 05:35:01PM -0800, Andrew Morton wrote: > On Wed, 19 Feb 2020 22:15:51 -0700 Nathan Chancellor wrote: > > > Clang warns: > > > > These are not true arrays, they are linker defined symbols, which are > > just addresses. Using the address of operator silences the warning and > > does not change the resulting assembly with either clang/ld.lld or > > gcc/ld (tested with diff + objdump -Dr). > > I guess you forgot to quote the clang output? Ugh yes, sorry. I can send a v3 later or here it is if you want to stitch it in: ../mm/kmemleak.c:1955:28: warning: array comparison always evaluates to a constant [-Wtautological-compare] if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata) ^ ../mm/kmemleak.c:1955:60: warning: array comparison always evaluates to a constant [-Wtautological-compare] if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata) ^ 2 warnings generated. Cheers, Nathan