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=-8.9 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,URIBL_BLOCKED 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 83086C2BA1A for ; Tue, 7 Apr 2020 03:10:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 42A2A20716 for ; Tue, 7 Apr 2020 03:10:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="vwP8fnc3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42A2A20716 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 E97C08E0084; Mon, 6 Apr 2020 23:10:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E48048E0062; Mon, 6 Apr 2020 23:10:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D866D8E0084; Mon, 6 Apr 2020 23:10:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0186.hostedemail.com [216.40.44.186]) by kanga.kvack.org (Postfix) with ESMTP id BC3C98E0062 for ; Mon, 6 Apr 2020 23:10:47 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 83A66180AD806 for ; Tue, 7 Apr 2020 03:10:47 +0000 (UTC) X-FDA: 76679581734.28.voice36_6e1c0e41f722 X-HE-Tag: voice36_6e1c0e41f722 X-Filterd-Recvd-Size: 2899 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf30.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Apr 2020 03:10:47 +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 470AC20769; Tue, 7 Apr 2020 03:10:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586229046; bh=0PsBwGSeoFEDRWNHEaX7Cv7d3vjlYWXCaC1rbrNWF9E=; h=Date:From:To:Subject:In-Reply-To:From; b=vwP8fnc3FfaYbHZe/R+p6OuhDFP5mZMOlfDzACT4RtDagsIDzTxq7U4MWa7kOX23z slY8KSiVgch6EkgsC6FKfPbTEI/fvILAeJ9UCIndxHv/oB6zI2gTdV1XurfVPSwNI+ fd7WvEZKMmG3YZuRlN2emuYbb1E3auyveq08eRUA= Date: Mon, 06 Apr 2020 20:10:45 -0700 From: Andrew Morton To: akpm@linux-foundation.org, jbaron@akamai.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, natechancellor@gmail.com, ndesaulniers@google.com, torvalds@linux-foundation.org Subject: [patch 126/166] lib/dynamic_debug.c: use address-of operator on section symbols Message-ID: <20200407031045.KqfxtQns2%akpm@linux-foundation.org> In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@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: lib/dynamic_debug.c: use address-of operator on section symbols Clang warns: ../lib/dynamic_debug.c:1034:24: warning: array comparison always evaluates to false [-Wtautological-compare] if (__start___verbose == __stop___verbose) { ^ 1 warning generated. 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/894 Link: http://lkml.kernel.org/r/20200220051320.10739-1-natechancellor@gmail.com Signed-off-by: Nathan Chancellor Suggested-by: Nick Desaulniers Acked-by: Jason Baron Signed-off-by: Andrew Morton --- lib/dynamic_debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/lib/dynamic_debug.c~dynamic_debug-use-address-of-operator-on-section-symbols +++ a/lib/dynamic_debug.c @@ -1031,7 +1031,7 @@ static int __init dynamic_debug_init(voi int n = 0, entries = 0, modct = 0; int verbose_bytes = 0; - if (__start___verbose == __stop___verbose) { + if (&__start___verbose == &__stop___verbose) { pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n"); return 1; } _