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=-19.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 99B36C07E95 for ; Sat, 10 Jul 2021 23:56:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8046061057 for ; Sat, 10 Jul 2021 23:56:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233841AbhGJX7B (ORCPT ); Sat, 10 Jul 2021 19:59:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:41376 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234114AbhGJX5t (ORCPT ); Sat, 10 Jul 2021 19:57:49 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C3E6E61428; Sat, 10 Jul 2021 23:52:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961170; bh=zsX6P8+wsgbmqJgIM2hsJSHm4Qlrw2k1kf5DeSgcSvU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GvZa2XTTMcz72H7HcLbwBE3bw43LcRmeqMQXojKWP05Ru7uJz04OEcxJ1lbdqOQ+z sVWtEX9ZaTVFn9hsNGvAS2FFnivZ7oP7Fe6kNEl0EW2aL8w0d1nDwx4FJP1JvQju5i Jr8iyeQzdlnB7hRhdMDj0VZ4bzPCe6VoJRKHkEk0L/iNiSybh2XAn5RQ9ALCBkhX/o 3HP8R8uDP3SbfPC9jmWkNQsE+nFu8tfgQuM1/LgRaxDgkVxoFFEXFrzTjiCD1wW9I2 GCS5CYjo07srAKWH+CcWHINfF80FQ52RW/sbblBV7LWU/6W+fc8qnyW1m+GfqUjRc8 p5Ifxpkdh+sRg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zou Wei , Hulk Robot , Guenter Roeck , Vladimir Zapolskiy , Wim Van Sebroeck , Sasha Levin , linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 4.9 07/16] watchdog: Fix possible use-after-free by calling del_timer_sync() Date: Sat, 10 Jul 2021 19:52:31 -0400 Message-Id: <20210710235240.3222618-7-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210710235240.3222618-1-sashal@kernel.org> References: <20210710235240.3222618-1-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: stable@vger.kernel.org From: Zou Wei [ Upstream commit d0212f095ab56672f6f36aabc605bda205e1e0bf ] This driver's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself. Reported-by: Hulk Robot Signed-off-by: Zou Wei Reviewed-by: Guenter Roeck Acked-by: Vladimir Zapolskiy Link: https://lore.kernel.org/r/1620802676-19701-1-git-send-email-zou_wei@huawei.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck Signed-off-by: Sasha Levin --- drivers/watchdog/lpc18xx_wdt.c | 2 +- drivers/watchdog/w83877f_wdt.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/watchdog/lpc18xx_wdt.c b/drivers/watchdog/lpc18xx_wdt.c index fd171e6caa16..1b63d1d85aa0 100644 --- a/drivers/watchdog/lpc18xx_wdt.c +++ b/drivers/watchdog/lpc18xx_wdt.c @@ -300,7 +300,7 @@ static int lpc18xx_wdt_remove(struct platform_device *pdev) struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev); dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n"); - del_timer(&lpc18xx_wdt->timer); + del_timer_sync(&lpc18xx_wdt->timer); watchdog_unregister_device(&lpc18xx_wdt->wdt_dev); clk_disable_unprepare(lpc18xx_wdt->wdt_clk); diff --git a/drivers/watchdog/w83877f_wdt.c b/drivers/watchdog/w83877f_wdt.c index f0483c75ed32..4b52cf321747 100644 --- a/drivers/watchdog/w83877f_wdt.c +++ b/drivers/watchdog/w83877f_wdt.c @@ -170,7 +170,7 @@ static void wdt_startup(void) static void wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); wdt_change(WDT_DISABLE); -- 2.30.2