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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 DF40BC07E95 for ; Mon, 19 Jul 2021 15:06:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE4416024A for ; Mon, 19 Jul 2021 15:06:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242559AbhGSOZT (ORCPT ); Mon, 19 Jul 2021 10:25:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:56408 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242693AbhGSOWn (ORCPT ); Mon, 19 Jul 2021 10:22:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 811FC6113A; Mon, 19 Jul 2021 15:02:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626706966; bh=8vf89cqAEiEpOFAna+3saqsBdZd00cUqtRl2GaRnTcw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f/qEgyNM6ybIrALhj5Kyw2R9kczfrTmCpF/VPMGqcEWCn2zsIeuOUgb8pqR9ajn+Q dYIUFfJtSZY77vaQsrX1thBtYasnw9Gp/JuDJq8tvBON9U8LYEZRbRKSHiNiXINvUo fSfK02c8jHVtfOt8o+QCDy+cIRhfu4AEDGF0qWpw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hulk Robot , Zou Wei , Guenter Roeck , Wim Van Sebroeck , Sasha Levin Subject: [PATCH 4.4 168/188] watchdog: Fix possible use-after-free in wdt_startup() Date: Mon, 19 Jul 2021 16:52:32 +0200 Message-Id: <20210719144941.989363258@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144913.076563739@linuxfoundation.org> References: <20210719144913.076563739@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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