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,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_NONE,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 114A2C11F66 for ; Sat, 10 Jul 2021 23:55:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE78B6135E for ; Sat, 10 Jul 2021 23:55:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234347AbhGJX5r (ORCPT ); Sat, 10 Jul 2021 19:57:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:40528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231700AbhGJX4a (ORCPT ); Sat, 10 Jul 2021 19:56:30 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 30130613E9; Sat, 10 Jul 2021 23:52:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961141; bh=8vf89cqAEiEpOFAna+3saqsBdZd00cUqtRl2GaRnTcw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ajEeAm1BAHDBj+POxAUVheMhShVi/2AEgVE4x/6PPDFiIiJ9p3lxsdQxQwfquxUCH KST7Glh6delMlcf27E5fdQUv6zg50vPkHDqMtCO4j/xKwOEA7xru5HecKFu5Nua6Ky UMRz4Ymf2fGaRIQHMdh6T5CgZ4uy1DVKtcDz7zdkaiqqnIs9sg9ATokZVU7GDi+fJ5 1njP7O86QtvrvuKUlZ7I5GwgTYOvPpDHtLX0iWKqDqtkAYS2Sazpvs1zs/qyM31Uk8 5Q1TiOEx0DZrPzmBqiV6RtA4Ko6N1441KGG4qruRNVMADeTt3gdQnHNBPNP9YebRGs QX2wcbDdTjJaw== 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 4.14 06/21] watchdog: Fix possible use-after-free in wdt_startup() Date: Sat, 10 Jul 2021 19:51:57 -0400 Message-Id: <20210710235212.3222375-6-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210710235212.3222375-1-sashal@kernel.org> References: <20210710235212.3222375-1-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 c08a6b31e4917034f0ed0cb457c3bb209576f542 ] 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/1620716495-108352-1-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/sbc60xxwdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/watchdog/sbc60xxwdt.c b/drivers/watchdog/sbc60xxwdt.c index 2eef58a0cf05..152db059d5aa 100644 --- a/drivers/watchdog/sbc60xxwdt.c +++ b/drivers/watchdog/sbc60xxwdt.c @@ -152,7 +152,7 @@ static void wdt_startup(void) static void wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); inb_p(wdt_stop); pr_info("Watchdog timer is now disabled...\n"); } -- 2.30.2