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=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 3360BC07E9B for ; Mon, 19 Jul 2021 15:06:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FD11611C1 for ; Mon, 19 Jul 2021 15:06:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243067AbhGSOZa (ORCPT ); Mon, 19 Jul 2021 10:25:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:56252 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242691AbhGSOWm (ORCPT ); Mon, 19 Jul 2021 10:22:42 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 32BB761165; Mon, 19 Jul 2021 15:02:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626706968; bh=Z1n8wsZv+jOd5MN9VkohCRg6WHiM6xigm4+S3agCXjg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VbQI8yH+3RyhSsBwnWxOfK8J98FYSI/N12ui++ETn8spp18ArMbr4vLZ5lEFO8Ok9 kXsv2VCFSi1JJ6OWi0IFH7+MgjIQZjeE/Ed+dQ+s8AS4ysO7j/i97nP5u+AlYQjBfF nabG7HNciHW9upSTLuaAQvgYsQ1QnGamjl0KxRF0= 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 4.4 169/188] watchdog: sc520_wdt: Fix possible use-after-free in wdt_turnoff() Date: Mon, 19 Jul 2021 16:52:33 +0200 Message-Id: <20210719144942.020394029@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 90b7c141132244e8e49a34a4c1e445cce33e07f4 ] 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/1620716691-108460-1-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/sc520_wdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/watchdog/sc520_wdt.c b/drivers/watchdog/sc520_wdt.c index 1cfd3f6a13d5..08500db8324f 100644 --- a/drivers/watchdog/sc520_wdt.c +++ b/drivers/watchdog/sc520_wdt.c @@ -190,7 +190,7 @@ static int wdt_startup(void) static int wdt_turnoff(void) { /* Stop the timer */ - del_timer(&timer); + del_timer_sync(&timer); /* Stop the watchdog */ wdt_config(0); -- 2.30.2