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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 2B1FDC07E9C for ; Mon, 12 Jul 2021 08:29:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12D2661443 for ; Mon, 12 Jul 2021 08:29:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353435AbhGLI3e (ORCPT ); Mon, 12 Jul 2021 04:29:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:50354 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241121AbhGLHmO (ORCPT ); Mon, 12 Jul 2021 03:42:14 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 37489601FE; Mon, 12 Jul 2021 07:39:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626075564; bh=qTMTGeV9ciYP7Qn8FcEjRuogBwwuHoI6ciBk60nevYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M309S8M0SMRocpJ2faZOiJnCvuFK+647jrcr19U4IHOIL6Tdsq2SlvA+a/WJy6Y7Y 4bo7jyy27Tm1oYkJWNh1mI81mnyp32lk4CrRoAIhiVhJoxzcD6oXd60+FGdXrG8Te2 yi/0D9Qex20P7jHiW68oiGDCFIdvgXQuY3ZI+O0o= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Shevchenko , Mark Brown , Sasha Levin Subject: [PATCH 5.13 268/800] spi: Avoid undefined behaviour when counting unused native CSs Date: Mon, 12 Jul 2021 08:04:51 +0200 Message-Id: <20210712060952.435549469@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060912.995381202@linuxfoundation.org> References: <20210712060912.995381202@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Shevchenko [ Upstream commit f60d7270c8a3d2beb1c23ae0da42497afa3584c2 ] ffz(), that has been used to count unused native CSs, might cause undefined behaviour when called against ~0U. To fix that, open code it with ffs(~value) - 1. Fixes: 7d93aecdb58d ("spi: Add generic support for unused native cs with cs-gpios") Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20210420164425.40287-2-andriy.shevchenko@linux.intel.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index ae04ae79e56a..56c173869d97 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2622,7 +2622,7 @@ static int spi_get_gpio_descs(struct spi_controller *ctlr) native_cs_mask |= BIT(i); } - ctlr->unused_native_cs = ffz(native_cs_mask); + ctlr->unused_native_cs = ffs(~native_cs_mask) - 1; if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios && ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) { -- 2.30.2