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 56B05C07E9B for ; Sat, 10 Jul 2021 23:52:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D9F4613B5 for ; Sat, 10 Jul 2021 23:52:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233389AbhGJXz0 (ORCPT ); Sat, 10 Jul 2021 19:55:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:40316 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233425AbhGJXya (ORCPT ); Sat, 10 Jul 2021 19:54:30 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 95F22613AF; Sat, 10 Jul 2021 23:51:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961080; bh=ms9YRNTIYNavmZmPXDww3mZ1tmy/t85F9z+8UsdPNmQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FICOR2iclACOn4bbJClUP38dDtQB+n35JpTogonOmMox9tb4xYcfwZbu8cLBwc9qS VL12/U2VMgvYnEk+AH9gvC9VBc9i2a1QIDUWTkxiMYdk+Js/iCfc2Xjasd5LZcolG4 VN9Bqorui7BjgC1R0/Vbd/C3OZS2ZkkqLddrmuB+u1mExBO3kKzY9PpsKcZqo9tNWR 0tag2JG/+3+D8lO8jAjNM2PLnLcgDXRMfTG4OdNZGjGGTMFnJeE8v8SL2Jq82CfARs CQO+XzVX+DOtCVn2TwjVTEjHVTTqf1GUrUlApK3acRRxpLrQmsuYiEXl2hlTxrW9Ou YWq+czRsmRIzA== 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 10/28] watchdog: sc520_wdt: Fix possible use-after-free in wdt_turnoff() Date: Sat, 10 Jul 2021 19:50:49 -0400 Message-Id: <20210710235107.3221840-10-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 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 a612128c5f80..57969564c7f9 100644 --- a/drivers/watchdog/sc520_wdt.c +++ b/drivers/watchdog/sc520_wdt.c @@ -186,7 +186,7 @@ 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