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 31607C11F66 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 13A2061057 for ; Sat, 10 Jul 2021 23:58:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233875AbhGKAAz (ORCPT ); Sat, 10 Jul 2021 20:00:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:47600 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231791AbhGJX6d (ORCPT ); Sat, 10 Jul 2021 19:58:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E5FE761184; Sat, 10 Jul 2021 23:53:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961189; bh=8vf89cqAEiEpOFAna+3saqsBdZd00cUqtRl2GaRnTcw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KLrlfmuReufvrOQy0SXod+3s517tmrF0MTvxMDmZI6GBXhgE5AcBvEojfPYI8Fdu6 U5SW5pY2TtwXEpWAZa/FQA2nDzBSdK2w01Zz/RrK2rWMN/vuAFu70wIjroCcsO1PwJ 9m4cvGv8R5H1q7PM+eB+H/aVZatM/UXu+rNUmODt3/5jlBur04/PYDr9o5fLZgU6bg h1wObh3JCz3d0IX3frj925IO5qWauyeXTouGBWppi9A/hPF2s0oN56ObYirk0w68yL /dNPIsudu1GIpHCihl+UiItGiimtBicfiK77rhYqhgeolz2s6mMydC3zYNQyiBtPNr HZdTyq3R5mfZg== 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 05/12] watchdog: Fix possible use-after-free in wdt_startup() Date: Sat, 10 Jul 2021 19:52:55 -0400 Message-Id: <20210710235302.3222809-5-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 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