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 0FC46C11F68 for ; Sat, 10 Jul 2021 23:52:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F36AC613B5 for ; Sat, 10 Jul 2021 23:52:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233595AbhGJXz1 (ORCPT ); Sat, 10 Jul 2021 19:55:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:39778 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233699AbhGJXya (ORCPT ); Sat, 10 Jul 2021 19:54:30 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0101B61362; Sat, 10 Jul 2021 23:51:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961082; bh=eWAWdoYUyGT4tcyRnagC6znYfXGQBgaN1dR66rV/snc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bFFZEr5Fh0o47HJpzIS5LhZXyv6y47GFvEVMyy8ukL04JasTPnRA7uCht3oZdKgNV mY/AVta6r3yHJCzXoz9FOqRezwJIRDo7CH3oAWlIFJ3fPz8LHDkJxYWCOGYeu8RjKm BVU2ZEzBgUU6Rsd+9A/UU+aoXo1pMVhu4uaSEweMw7YXSGb4lT+zQze1A1Gz2grpfs kz3kSukTfTx1DL0QgBvUbhpTUt8g+4b3IWqK5tvsCBwF26ChX3yETBPbAtz1Xiy9QZ LwNU/WEGjkJ8MEcaJfxcztfxkMR1SYc/YW7lAnEk7/ELaLqN3TmQuC0eMRW7AXTSpS TbofHxr3V3Vsw== 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 5.4 11/28] watchdog: Fix possible use-after-free by calling del_timer_sync() Date: Sat, 10 Jul 2021 19:50:50 -0400 Message-Id: <20210710235107.3221840-11-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 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 78cf11c94941..60b6d74f267d 100644 --- a/drivers/watchdog/lpc18xx_wdt.c +++ b/drivers/watchdog/lpc18xx_wdt.c @@ -292,7 +292,7 @@ static int lpc18xx_wdt_remove(struct platform_device *pdev) struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev); dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n"); - del_timer(&lpc18xx_wdt->timer); + del_timer_sync(&lpc18xx_wdt->timer); return 0; } diff --git a/drivers/watchdog/w83877f_wdt.c b/drivers/watchdog/w83877f_wdt.c index 6eb5185d6ea6..d9addf06b44d 100644 --- a/drivers/watchdog/w83877f_wdt.c +++ b/drivers/watchdog/w83877f_wdt.c @@ -166,7 +166,7 @@ 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