From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752977AbcEZF7w (ORCPT ); Thu, 26 May 2016 01:59:52 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:42136 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751134AbcEZF7v (ORCPT ); Thu, 26 May 2016 01:59:51 -0400 Subject: Re: [PATCH] phy: exynos-mipi-video: avoid uninitialized variable use To: Arnd Bergmann , Krzysztof Kozlowski References: <1462971012-562097-1-git-send-email-arnd@arndb.de> <20160511185155.GB8265@kozik-lap> <14219690.YQPrXjp7cP@wuerfel> CC: Kukjin Kim , Krzysztof Kozlowski , Sylwester Nawrocki , Marek Szyprowski , , , From: Kishon Vijay Abraham I Message-ID: <574690B2.9010204@ti.com> Date: Thu, 26 May 2016 11:29:14 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <14219690.YQPrXjp7cP@wuerfel> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Arnd, On Thursday 26 May 2016 12:24 AM, Arnd Bergmann wrote: > On Wednesday, May 11, 2016 8:51:55 PM CEST Krzysztof Kozlowski wrote: >> On Wed, May 11, 2016 at 02:49:53PM +0200, Arnd Bergmann wrote: >>> A rework of the exynos-mipi-video driver caused a warning >>> about the new __set_phy_state function potentially accessing >>> a variable before its initialization: >>> >>> drivers/phy/phy-exynos-mipi-video.c: In function '__set_phy_state': >>> drivers/phy/phy-exynos-mipi-video.c:238:13: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized] >>> return val & data->resetn_val; >>> ~~~~^~~~~~~~~~~~~~~~~~ >>> drivers/phy/phy-exynos-mipi-video.c:235:6: note: 'val' was declared here >>> u32 val; >>> >>> The failure scenario here is the offset passed into a the >>> stub regmap_read() function that does not modify its output, >>> however regmap_read() can also fail for other reasons, so >>> adding error handling (in this case, returning zero from >>> is_running) seems the best solution. >>> >>> Note that this warning showed up with the ARM s5pv210_defconfig, >>> indicating that we most likely want to either enable CONFIG_REGMAP >>> in that defconfig as well, or disable the phy-exynos-mipi-video >>> driver. >>> >>> Signed-off-by: Arnd Bergmann >>> Fixes: 97a3042f7616 ("phy: exynos-mipi-video: Rewrite handling of phy registers") >>> --- >>> drivers/phy/phy-exynos-mipi-video.c | 6 +++++- >>> 1 file changed, 5 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/phy/phy-exynos-mipi-video.c b/drivers/phy/phy-exynos-mipi-video.c >>> index cc093ebfda94..8b851f718123 100644 >>> --- a/drivers/phy/phy-exynos-mipi-video.c >>> +++ b/drivers/phy/phy-exynos-mipi-video.c >>> @@ -233,8 +233,12 @@ static inline int __is_running(const struct exynos_mipi_phy_desc *data, >>> struct exynos_mipi_video_phy *state) >>> { >>> u32 val; >> >> Other way would be to initialize val=0 since there is no real error code >> returned. Anyway: >> >> Reviewed-by: Krzysztof Kozlowski > > > This hasn't made it into linux-next yet, any chance we'll see it in -rc1 or -rc2? Not in -rc1. Mostly it'll go in -rc2. Generally I start queuing patches after -rc1 is tagged. Thanks Kishon