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 8E0D3C11F76 for ; Sat, 10 Jul 2021 23:51:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 77DF8613DC for ; Sat, 10 Jul 2021 23:51:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233565AbhGJXx7 (ORCPT ); Sat, 10 Jul 2021 19:53:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:41308 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232775AbhGJXxZ (ORCPT ); Sat, 10 Jul 2021 19:53:25 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 389686139A; Sat, 10 Jul 2021 23:50:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625961039; bh=4l/AoMsvGwjk7Lsth8aoRoQQpUwOUt4rTVkI0sOT9vM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TE6JovPzR6zvKsghLdm1tD1Vdtebtcvos95PVBpMois3LJZ9gSNjBks+6KZxUKVuz 2sYAIk2IkHMjSwCMEjPa5YvwMmH1JcCr55mktz7nI63XA76mqlr59FwpyLtp9THfYj MwIfb82c0JjV9htX9ZKsJkaNdmwzqVQ/UNYnHqq8VooGACQBnuwr/woRb4ixZYgJ9Z aITr5fcSPh7SlnvWfyHYKS1rkTEWwCrGSaFDmH7KveFNINQpdaFynTM77ZIrNepZTD mw7vgEVTaodh76atdIfNmeZv/BeBFRIf/mOQUzKLZRKlOx3AEGxhtYMs9ude/q1r4/ YcjQmSJdNdzcA== 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 5.10 16/37] watchdog: Fix possible use-after-free by calling del_timer_sync() Date: Sat, 10 Jul 2021 19:49:54 -0400 Message-Id: <20210710235016.3221124-16-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210710235016.3221124-1-sashal@kernel.org> References: <20210710235016.3221124-1-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 5772cc5d3780..f2650863fd02 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