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=ham 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 C2741C11F6A for ; Sat, 10 Jul 2021 23:58:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A93CE611B0 for ; Sat, 10 Jul 2021 23:58:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233106AbhGKAAz (ORCPT ); Sat, 10 Jul 2021 20:00:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:48526 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233227AbhGJX6d (ORCPT ); Sat, 10 Jul 2021 19:58:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 48426613D7; Sat, 10 Jul 2021 23:53:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961191; bh=Z1n8wsZv+jOd5MN9VkohCRg6WHiM6xigm4+S3agCXjg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gjDTp449YII5OHNc1xtkv4LRj8SVhRmkIYPlJNk9TUQwtK85P2ncxqkTms6OhwPP4 YqKhtR3AzNpeODbm1KcG9E63gH4JE6K8BJO+BYB3D+MA61nRwQmMh3LWK5AW3uT+TB v4AuDl1/aVplJ77PA0nYuTMqEmphEADthDilN3ob/NlpFx/u34Frkb5QCDuj/zeJk8 cPHe5n22enDfQ08yvlqgxmd+KH7xTjs1ep78dj4fh8FLPOjYaAs8a61o5kc8TmvKc8 tjxBpmVqTbzcY55dk2ZE765dFkOa5Lphg1dQy4VyLGJuv+Pua/cB0bmnNP/mJ+V9Df 96Bj1pXrbT7mQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zou Wei , Hulk Robot , Guenter Roeck , Wim Van Sebroeck , Sasha Levin , linux-watchdog@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 06/12] watchdog: sc520_wdt: Fix possible use-after-free in wdt_turnoff() Date: Sat, 10 Jul 2021 19:52:56 -0400 Message-Id: <20210710235302.3222809-6-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210710235302.3222809-1-sashal@kernel.org> References: <20210710235302.3222809-1-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-watchdog@vger.kernel.org From: Zou Wei [ Upstream commit 90b7c141132244e8e49a34a4c1e445cce33e07f4 ] This module'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 Link: https://lore.kernel.org/r/1620716691-108460-1-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/sc520_wdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/watchdog/sc520_wdt.c b/drivers/watchdog/sc520_wdt.c index 1cfd3f6a13d5..08500db8324f 100644 --- a/drivers/watchdog/sc520_wdt.c +++ b/drivers/watchdog/sc520_wdt.c @@ -190,7 +190,7 @@ static int wdt_startup(void) static int wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); /* Stop the watchdog */ wdt_config(0); -- 2.30.2