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 3CA80C07E95 for ; Sat, 10 Jul 2021 23:52:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27721613F0 for ; Sat, 10 Jul 2021 23:52:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231766AbhGJXzN (ORCPT ); Sat, 10 Jul 2021 19:55:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:40226 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233606AbhGJXyO (ORCPT ); Sat, 10 Jul 2021 19:54:14 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5049C613BF; Sat, 10 Jul 2021 23:51:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961079; bh=ZZadxa0w8dtzQqSSAXWpiz/dHqayTUoeHiO1uRLZiEI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kuQvc+uh5SI28uuM+Agw7O31Zy0sgXaRcVkosgAFFDjwuOGh6W+mmZQ5PeUqcQ4j5 5+SALzY3W5HyYlv/9/jK70+bpykjn7AZc9qsEbTo7eDqGxy3NQt2ul4I4dydg6pUdq T1nEaqvjJn0YcRyebIFOtmBJH+bbZkJKizR4vjLA9mqVyCCjroHL9FqF9L4TF6Wf8s 1xZfZH5T8tT1Z5LmYj+QcDdvALEe8vQSqQkxincQi/fu97I9Hk4PRtkopKJP9cs9ON uw8nw7IhexdqM1+hYOFvuH7ajNKTI2zrd+e7LG0LoNdl+V1bZZBHHb5mo7k70geQ+D Bv3WYP+Jn1PFw== 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 5.4 09/28] watchdog: Fix possible use-after-free in wdt_startup() Date: Sat, 10 Jul 2021 19:50:48 -0400 Message-Id: <20210710235107.3221840-9-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210710235107.3221840-1-sashal@kernel.org> References: <20210710235107.3221840-1-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 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 c3151642694c..de1f7add05c3 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