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 1FB40C07E9B for ; Sat, 10 Jul 2021 23:54:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E6D8610A2 for ; Sat, 10 Jul 2021 23:54:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233850AbhGJX46 (ORCPT ); Sat, 10 Jul 2021 19:56:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:40502 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233612AbhGJXz2 (ORCPT ); Sat, 10 Jul 2021 19:55:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2029D613EB; Sat, 10 Jul 2021 23:51:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961112; bh=W3YjjptMEBGQZLlHyRQRxy/NRzcHtf1hsTFJCYNcqZA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GCSIMYYcRqomwITVP0SVJiiEBaP341JXkQu6g1qMg6wijpBl5+7e+PtbZMU5jj7DZ HUtHDls15SJ07r8S++EK0QLYtnXIzbjIq2BJXf1wEppgfQAQEW7+hKLgO2QvWZkoHS Zw2mbJQYUIEdMAv+G6Um+Nl5aGu+Vzz68Mbi6qipR9zi5aSfdfb5/ZDOjEFsOsJMab fqyPa8MqoGSK4Cq/GPJrXiXss6i6rH1T5PEz8ZgNUi9s2ByCAh9//hIGxWsitrCT1u hT2N/ZhfipLENxe3pMlypSagaTprxrwPA66ML1YnKIw46KbFWVfwaSm4GsRf8EsqeC hst236AtWOcqg== 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 4.19 06/22] watchdog: Fix possible use-after-free in wdt_startup() Date: Sat, 10 Jul 2021 19:51:27 -0400 Message-Id: <20210710235143.3222129-6-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210710235143.3222129-1-sashal@kernel.org> References: <20210710235143.3222129-1-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-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 87333a41f753..1702df7f8c38 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