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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1D3FC19F2A for ; Thu, 11 Aug 2022 15:36:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236119AbiHKPgY (ORCPT ); Thu, 11 Aug 2022 11:36:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235793AbiHKPfc (ORCPT ); Thu, 11 Aug 2022 11:35:32 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 76C8A9925B; Thu, 11 Aug 2022 08:32:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 161DDB82165; Thu, 11 Aug 2022 15:32:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C9991C433D7; Thu, 11 Aug 2022 15:32:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660231975; bh=ibPz3/kfU5FwqL/Jn2/MvmkAei/qwkLTQ9MhEGzmKqM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=da5j1YexMWGMWfIcTZWJ3yAGYJS+1pIrr6jadZa7dPsvVuokFzkiiJPNk4R/taAAw ovlseNr+XEOmZympiM3SmhiWEUkrPFIQ6oOOD1KZszDjrpYHoFFxbD13pGdw7OpK/C j2b3hJSJqCLOA9F20RyHz+eAtwLJKeC2rWGyDUO7pJhSpH/zz6Z8X/1p7mLg4KdDC+ r7a+PhsTal3H+NYmhaSepNI+xMMpVzXTf0TU66qgz1i0mT3Hq+NJRgPgob+fYJ5cCJ DUW2a6HUPWINO6RGYRWo4xqH11QQh24t23rkx53F/w+NRkPlwUBrtfTfD1ALcMqdol nEtiARFk3AQfg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ammar Faizi , Willy Tarreau , Alviro Iskandar Setiawan , "Paul E . McKenney" , Sasha Levin Subject: [PATCH AUTOSEL 5.19 036/105] tools/nolibc/stdlib: Support overflow checking for older compiler versions Date: Thu, 11 Aug 2022 11:27:20 -0400 Message-Id: <20220811152851.1520029-36-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220811152851.1520029-1-sashal@kernel.org> References: <20220811152851.1520029-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ammar Faizi [ Upstream commit 1ef150cf40be986747c3fa0c0e75acaec412e85e ] Previously, we used __builtin_mul_overflow() to check for overflow in the multiplication operation in the calloc() function. However, older compiler versions don't support this built-in. This patch changes the overflow checking mechanism to make it work on any compiler version by using a division method to check for overflow. No functional change intended. While in there, remove the unused variable `void *orig`. Link: https://lore.kernel.org/lkml/20220330024114.GA18892@1wt.eu Suggested-by: Willy Tarreau Cc: Alviro Iskandar Setiawan Signed-off-by: Ammar Faizi Acked-by: Willy Tarreau Reviewed-by: Alviro Iskandar Setiawan Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin --- tools/include/nolibc/stdlib.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/tools/include/nolibc/stdlib.h b/tools/include/nolibc/stdlib.h index 8fd32eaf8037..92378c4b9660 100644 --- a/tools/include/nolibc/stdlib.h +++ b/tools/include/nolibc/stdlib.h @@ -128,10 +128,9 @@ void *malloc(size_t len) static __attribute__((unused)) void *calloc(size_t size, size_t nmemb) { - void *orig; - size_t res = 0; + size_t x = size * nmemb; - if (__builtin_expect(__builtin_mul_overflow(nmemb, size, &res), 0)) { + if (__builtin_expect(size && ((x / size) != nmemb), 0)) { SET_ERRNO(ENOMEM); return NULL; } @@ -140,7 +139,7 @@ void *calloc(size_t size, size_t nmemb) * No need to zero the heap, the MAP_ANONYMOUS in malloc() * already does it. */ - return malloc(res); + return malloc(x); } static __attribute__((unused)) -- 2.35.1