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 62DEFC636CE for ; Mon, 19 Jul 2021 16:27:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 50AB161450 for ; Mon, 19 Jul 2021 16:27:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244801AbhGSPqm (ORCPT ); Mon, 19 Jul 2021 11:46:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:43682 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349159AbhGSPoy (ORCPT ); Mon, 19 Jul 2021 11:44:54 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8D71061450; Mon, 19 Jul 2021 16:23:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626711826; bh=0rOQmzH2/RHjeIWMPO1I5FaTDOuQ4tbgwtr7wXAqSH0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kqNkh8O4oMzz7gVvbdjWN336094c8dmoFPFs3WmgfsGxd8O3W4FIQdzZoNtRGDYdn KnzD2fVxJ3/cZDXxZ4z60f9YE/CG4S7t2/j7UZZQ68xH3CTCn6HaNX0Hv1kLoVQEYs 53k1qby7wBD77wA6JnfQfJlpVEWf2gnw+Vixp5PE= 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 5.12 145/292] watchdog: Fix possible use-after-free in wdt_startup() Date: Mon, 19 Jul 2021 16:53:27 +0200 Message-Id: <20210719144947.251827507@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144942.514164272@linuxfoundation.org> References: <20210719144942.514164272@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: 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 a947a63fb44a..7b974802dfc7 100644 --- a/drivers/watchdog/sbc60xxwdt.c +++ b/drivers/watchdog/sbc60xxwdt.c @@ -146,7 +146,7 @@ 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