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=-8.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,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 12EA3C43331 for ; Thu, 2 Apr 2020 04:04:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BE137206E9 for ; Thu, 2 Apr 2020 04:04:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="bbxQby+8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE137206E9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 702A48E0011; Thu, 2 Apr 2020 00:04:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6899B8E000D; Thu, 2 Apr 2020 00:04:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 59F948E0011; Thu, 2 Apr 2020 00:04:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0238.hostedemail.com [216.40.44.238]) by kanga.kvack.org (Postfix) with ESMTP id 3DE7B8E000D for ; Thu, 2 Apr 2020 00:04:36 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 07D43180AD80F for ; Thu, 2 Apr 2020 04:04:36 +0000 (UTC) X-FDA: 76661573352.26.cart08_28216f724f828 X-HE-Tag: cart08_28216f724f828 X-Filterd-Recvd-Size: 3281 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Thu, 2 Apr 2020 04:04:35 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AFC4920747; Thu, 2 Apr 2020 04:04:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585800275; bh=qjcHU9kjnAUy6sP3FsQgkVazXZL0L3CSTJvr6TE0rR4=; h=Date:From:To:Subject:In-Reply-To:From; b=bbxQby+8H5hfKq1iWbSY95KU+kgWvY7wA6VAyWIVnfxzdXdy4NYEezSZbbvfrhDIu ad9P9u3YdSEmTUPsZXmdiGrv1dyrZgDPs8KJ94QD6N5laeCr82RwuBBZig/cfPOAGy yVEVzSCHHZfPKX3ZLlz74xHb1GWkNiVU3bPWZuQ4= Date: Wed, 01 Apr 2020 21:04:34 -0700 From: Andrew Morton To: akpm@linux-foundation.org, catalin.marinas@arm.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, natechancellor@gmail.com, ndesaulniers@google.com, torvalds@linux-foundation.org Subject: [patch 027/155] mm/kmemleak.c: use address-of operator on section symbols Message-ID: <20200402040434.YaKEjoeES%akpm@linux-foundation.org> In-Reply-To: <20200401210155.09e3b9742e1c6e732f5a7250@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Nathan Chancellor Subject: mm/kmemleak.c: use address-of operator on section symbols Clang warns: ../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) 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). Link: https://github.com/ClangBuiltLinux/linux/issues/895 Link: http://lkml.kernel.org/r/20200220051551.44000-1-natechancellor@gmail.com Suggested-by: Nick Desaulniers Signed-off-by: Nathan Chancellor Acked-by: Catalin Marinas Signed-off-by: Andrew Morton --- mm/kmemleak.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/kmemleak.c~mm-kmemleak-use-address-of-operator-on-section-symbols +++ a/mm/kmemleak.c @@ -1947,7 +1947,7 @@ void __init kmemleak_init(void) create_object((unsigned long)__bss_start, __bss_stop - __bss_start, KMEMLEAK_GREY, GFP_ATOMIC); /* only register .data..ro_after_init if not within .data */ - if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata) + if (&__start_ro_after_init < &_sdata || &__end_ro_after_init > &_edata) create_object((unsigned long)__start_ro_after_init, __end_ro_after_init - __start_ro_after_init, KMEMLEAK_GREY, GFP_ATOMIC); _