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 9CE91C77B6C for ; Thu, 13 Apr 2023 02:37:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229739AbjDMChC (ORCPT ); Wed, 12 Apr 2023 22:37:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35070 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229899AbjDMCgn (ORCPT ); Wed, 12 Apr 2023 22:36:43 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E27FD83FC; Wed, 12 Apr 2023 19:36:28 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 155CA63A9C; Thu, 13 Apr 2023 02:36:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF4BBC433D2; Thu, 13 Apr 2023 02:36:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1681353382; bh=q5WtqATHSEDJyHfny5vrSARBb3qcLAUJXK6AMpRQOiY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aFCByTVyWJf7QFKRUaP6SlIUkNV+Wt1obvHTWcH2hDTVdGWlYtCazIxsvYtDg+rdA 3EzlUtYSeMeo4BNDH1PUQ1YdnGjXich3k+qeElqQ3oE35sokOUjGw8bJIIqX5W/fAU zkpWClgqhQqKrdHx3cADlZAakqmmvq0avEWtTGvnKOX2SEr2ItKBHnF0cVBKSaNACG QMSanAcLFrYKS7LBwOPTQ1ZCZLATRXCwd8c9q5RFo4K+mEszUAg5oXg2Pmn79t/Ac3 +d8o/jnwHSB4WC1ftbsFMkSB6NgQUTZPfl2KiCS0xe+WWPFEF+NoeI5oTsjR4MNeaG bcEL9e8ORxYIA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Munehisa Kamata , Thierry Reding , Sasha Levin , linux-pwm@vger.kernel.org Subject: [PATCH AUTOSEL 6.2 08/20] pwm: Zero-initialize the pwm_state passed to driver's .get_state() Date: Wed, 12 Apr 2023 22:35:46 -0400 Message-Id: <20230413023601.74410-8-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230413023601.74410-1-sashal@kernel.org> References: <20230413023601.74410-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Uwe Kleine-König [ Upstream commit 1271a7b98e7989ba6bb978e14403fc84efe16e13 ] This is just to ensure that .usage_power is properly initialized and doesn't contain random stack data. The other members of struct pwm_state should get a value assigned in a successful call to .get_state(). So in the absence of bugs in driver implementations, this is only a safe-guard and no fix. Reported-by: Munehisa Kamata Link: https://lore.kernel.org/r/20230310214004.2619480-1-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding Signed-off-by: Sasha Levin --- drivers/pwm/core.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index e01147f66e15a..474725714a05b 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -115,7 +115,14 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) } if (pwm->chip->ops->get_state) { - struct pwm_state state; + /* + * Zero-initialize state because most drivers are unaware of + * .usage_power. The other members of state are supposed to be + * set by lowlevel drivers. We still initialize the whole + * structure for simplicity even though this might paper over + * faulty implementations of .get_state(). + */ + struct pwm_state state = { 0, }; err = pwm->chip->ops->get_state(pwm->chip, pwm, &state); trace_pwm_get(pwm, &state, err); @@ -448,7 +455,7 @@ static void pwm_apply_state_debug(struct pwm_device *pwm, { struct pwm_state *last = &pwm->last; struct pwm_chip *chip = pwm->chip; - struct pwm_state s1, s2; + struct pwm_state s1 = { 0 }, s2 = { 0 }; int err; if (!IS_ENABLED(CONFIG_PWM_DEBUG)) @@ -530,6 +537,7 @@ static void pwm_apply_state_debug(struct pwm_device *pwm, return; } + *last = (struct pwm_state){ 0 }; err = chip->ops->get_state(chip, pwm, last); trace_pwm_get(pwm, last, err); if (err) -- 2.39.2