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 7D1F0C11F6C for ; Sat, 10 Jul 2021 23:58:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6368261184 for ; Sat, 10 Jul 2021 23:58:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232995AbhGKAA4 (ORCPT ); Sat, 10 Jul 2021 20:00:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:48528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231183AbhGJX6e (ORCPT ); Sat, 10 Jul 2021 19:58:34 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B5D9E613E5; Sat, 10 Jul 2021 23:53:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961192; bh=hkADfCiMoQJ+risbIzZYtyX+fRNEebwVd2J4+7NsjoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K+473WzxsJVlMlI//5oz5nzQQNOxdhQGKBoJNNY//jdtvWq4DTNwPt0D28QWlg1Tj /JYyCnVVdB3W5huPFWyomPPOC8L940caP6iSYMq937iEaXfAkumnUfAED0PoiHF/kE 8u+KgFBUUUvJH/E4BXU9Myzl3r56TNmBEne4Qpsk3SR41GhJopQZ1skiJDZ8BragOA dkkGqN20bQCLxd1g9fNKGrM6TE2d2rawFBknjUJPI8BiZ1LcI8bFu6nJV/y12nlb38 umQ7pS6ngTCeo/5jc9QXsKdcjhBs2RrI/LJI3sr/HrXPfxGqx8s36z+bwqzI7nn0hm 0+kO4yYtJkaXQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zou Wei , Hulk Robot , Guenter Roeck , Vladimir Zapolskiy , Wim Van Sebroeck , Sasha Levin , linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 4.4 07/12] watchdog: Fix possible use-after-free by calling del_timer_sync() Date: Sat, 10 Jul 2021 19:52:57 -0400 Message-Id: <20210710235302.3222809-7-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 d0212f095ab56672f6f36aabc605bda205e1e0bf ] This driver'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 Acked-by: Vladimir Zapolskiy Link: https://lore.kernel.org/r/1620802676-19701-1-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/lpc18xx_wdt.c | 2 +- drivers/watchdog/w83877f_wdt.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/watchdog/lpc18xx_wdt.c b/drivers/watchdog/lpc18xx_wdt.c index ab7b8b185d99..fbdc0f32e666 100644 --- a/drivers/watchdog/lpc18xx_wdt.c +++ b/drivers/watchdog/lpc18xx_wdt.c @@ -309,7 +309,7 @@ static int lpc18xx_wdt_remove(struct platform_device *pdev) unregister_restart_handler(&lpc18xx_wdt->restart_handler); dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n"); - del_timer(&lpc18xx_wdt->timer); + del_timer_sync(&lpc18xx_wdt->timer); watchdog_unregister_device(&lpc18xx_wdt->wdt_dev); clk_disable_unprepare(lpc18xx_wdt->wdt_clk); diff --git a/drivers/watchdog/w83877f_wdt.c b/drivers/watchdog/w83877f_wdt.c index f0483c75ed32..4b52cf321747 100644 --- a/drivers/watchdog/w83877f_wdt.c +++ b/drivers/watchdog/w83877f_wdt.c @@ -170,7 +170,7 @@ static void wdt_startup(void) static void wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); wdt_change(WDT_DISABLE); -- 2.30.2