From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 765A038F91; Thu, 18 Jul 2024 03:46:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721274377; cv=none; b=k8aJD6i5Okb78Xch7urmoQ08txSh0asJPXrgfhVDnctCb0AbuCIsSSD2PR3jiCRjlYXdNfszrm7pM3axGLLbgKbJUBRMFA2bGAxaarX5qaTI/1QClDA08Eo2t1+Az4FtIbZiklH0+IxQXqx0yddlDtsNwuUOyeIgf43Q12v5EUo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721274377; c=relaxed/simple; bh=TgyDblSb6DLChmBjwwEnBre4ru3uWNRP9SsYVOSJ+vM=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=fJpIRjXVMLZcMDb7eeXP72G2uyBfC0vZE1RDEl8S3ZYrr53EGWzY5qx5UtAf9oN4qAD1jExjRcABUyYIhqzFZkb/bhj4kQ9kjiHNA08UdAFXrWTL79lLaa/YJQqHtqfU5WDyY/ea4bUQrjI1Dmyvak0SZuYZquwu27aNrJX+uQk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=SUCMD5rC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="SUCMD5rC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C1A52C116B1; Thu, 18 Jul 2024 03:46:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1721274377; bh=TgyDblSb6DLChmBjwwEnBre4ru3uWNRP9SsYVOSJ+vM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=SUCMD5rCWj/oJLM3Ldv8h7XQMawBx92SJwIAPYTByVK2UJEpkBnkk3NSlYWo7z2mK 5EciqmWn1brjUmACgkQUojIOAvnG0c8isq24sN7BXmL+KxyrfEw4wsfd1ldjXPWM9y eQ0eRniOpEft0u7RUfWjGy1rEeaipAvzqeEW/0sE= Date: Wed, 17 Jul 2024 20:46:16 -0700 From: Andrew Morton To: Jiapeng Chong Cc: shuah@kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Abaci Robot Subject: Re: [PATCH -next] selftests/mm: mseal, self_elf: Fix warning comparing pointer to 0 Message-Id: <20240717204616.7a3d2465272d4f8fd1736831@linux-foundation.org> In-Reply-To: <20240718031039.69861-1-jiapeng.chong@linux.alibaba.com> References: <20240718031039.69861-1-jiapeng.chong@linux.alibaba.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 18 Jul 2024 11:10:39 +0800 Jiapeng Chong wrote: > Avoid pointer type value compared with 0 to make code clear. > > ./tools/testing/selftests/mm/mseal_test.c:486:27-28: WARNING comparing pointer to 0. > ./tools/testing/selftests/mm/mseal_test.c:1399:29-30: WARNING comparing pointer to 0. > > ... > > --- a/tools/testing/selftests/mm/mseal_test.c > +++ b/tools/testing/selftests/mm/mseal_test.c > @@ -481,9 +481,8 @@ static void test_seal_zero_address(void) > int prot; > > /* use mmap to change protection. */ > - ptr = sys_mmap(0, size, PROT_NONE, > - MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); > - FAIL_TEST_IF_FALSE(ptr == 0); > + ptr = sys_mmap(0, size, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); > + FAIL_TEST_IF_FALSE(!ptr); > @@ -1390,13 +1389,12 @@ static void test_seal_mremap_move_fixed_zero(bool seal) > /* > * MREMAP_FIXED can move the mapping to zero address > */ > - ret2 = mremap(ptr, size, 2 * page_size, MREMAP_MAYMOVE | MREMAP_FIXED, > - 0); > + ret2 = mremap(ptr, size, 2 * page_size, MREMAP_MAYMOVE | MREMAP_FIXED, 0); The author of this code chose to make it tractable in an 80-column display. It's best not to change that, without explanation.