From nobody Mon Feb 9 10:11:13 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9CB38C77B71 for ; Thu, 13 Apr 2023 07:00:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229618AbjDMHAR (ORCPT ); Thu, 13 Apr 2023 03:00:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229498AbjDMHAP (ORCPT ); Thu, 13 Apr 2023 03:00:15 -0400 Received: from m12.mail.163.com (m12.mail.163.com [220.181.12.198]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9659F7280 for ; Thu, 13 Apr 2023 00:00:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=aYYjM s6sgb58wXmA0ce7H6o1vGXUMJqQKzsl1vTbGpk=; b=jcmkrjdXcvS6G5KG6yHL2 KzWzP5OrsZiIFA3Mnmx8hhl1uLs5IVd/89uSq83Fc7yIgn6RrR+gVlXjc1IwRofs /uji6+DgA9dsQ3MvfYervGA6Pg+JnvCyxI5d/+zK2wwYdg1o2yxrUxmEXVYOTJ53 t5Lokij8JQJ3szKBc42I74= Received: from leanderwang-LC2.localdomain (unknown [111.206.145.21]) by zwqz-smtp-mta-g5-4 (Coremail) with SMTP id _____wC3x79gqDdkks5dBQ--.23663S2; Thu, 13 Apr 2023 14:59:44 +0800 (CST) From: Zheng Wang To: dri-devel@lists.freedesktop.org Cc: andrzej.hajda@intel.com, neil.armstrong@linaro.org, jonas@kwiboo.se, airlied@gmail.com, daniel@ffwll.ch, linux-kernel@vger.kernel.org, hackerzheng666@gmail.com, 1395428693sheep@gmail.com, alex000young@gmail.com, Zheng Wang Subject: [PATCH v2] drm/bridge: adv7511: fix use after free bug in adv7511_remove due to race condition Date: Thu, 13 Apr 2023 14:59:43 +0800 Message-Id: <20230413065943.198088-1-zyytlz.wz@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wC3x79gqDdkks5dBQ--.23663S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7Ary7JrW3XFWDtrW7Cry8Zrb_yoW8Ar4fp3 y3uF90krWUXFnrKa9rJF45Aa4rCw4Dtr1S9FZruwnIvrn8ZF18JrZ0yF15try7XrWkXa12 qr4UAFykWFn8AaUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziI38rUUUUU= X-Originating-IP: [111.206.145.21] X-CM-SenderInfo: h2113zf2oz6qqrwthudrp/1tbiGg1QU1aEE4gpSgACs8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In adv7511_probe, adv7511->hpd_work is bound with adv7511_hpd_work. adv7511_irq_process might be called to start the work. If we call adv7511_remove with an unfinished work. There may be a race condition. Here is the possible sequence: CPU0 CPU1 |adv7511_hpd_work adv7511_remove | cec_devnode_release | cec_unregister_adapter| cec_devnode_unregister| put_device(&devnode->dev);| cec_devnode_release | cec_delete_adapter | kfree(adap); | |cec_phys_addr_invalidate |//use adap Fix it by canceling the work before cleanup in adv7511_remove. This is the patch with new title in order to clarify the bug. Old patch is here. The root cause is the same as old one. https://lore.kernel.org/all/20230316160548.1566989-1-zyytlz.wz@163.com/ Fixes: 518cb7057a59 ("drm/bridge: adv7511: Use work_struct to defer hotplug= handing to out of irq context") Signed-off-by: Zheng Wang --- v2: - Fix space error from checkpacth script --- drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm= /bridge/adv7511/adv7511_drv.c index ddceafa7b637..e702a993fe6f 100644 --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c @@ -1349,6 +1349,10 @@ static void adv7511_remove(struct i2c_client *i2c) { struct adv7511 *adv7511 =3D i2c_get_clientdata(i2c); =20 + if (i2c->irq) + devm_free_irq(&i2c->dev, i2c->irq, adv7511); + cancel_work_sync(&adv7511->hpd_work); + adv7511_uninit_regulators(adv7511); =20 drm_bridge_remove(&adv7511->bridge); --=20 2.25.1