From patchwork Mon Mar 1 09:05:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 1445500 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-gpio-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=L6WarvyS; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4DpvWy2FB4z9sVw for ; Mon, 1 Mar 2021 20:06:38 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233692AbhCAJGN (ORCPT ); Mon, 1 Mar 2021 04:06:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:38038 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233698AbhCAJFt (ORCPT ); Mon, 1 Mar 2021 04:05:49 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7F47164DD0; Mon, 1 Mar 2021 09:05:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614589508; bh=rvD6Og3rqMKfJOFjvdy0rWdmzsvs8Xe8fGn3WwO5QKI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L6WarvySsXUtX/+T8zMSEzobUepKWJuKdjEaFW3yvmFLW/7GEyzT9O3fCKCmLDaHl DSk+Y9c+XkbsrDYoCUl5M5MPnLU5edGM8T+OaC5l+CdFd8CIerzAgxDlDI1lX2YuaD UxXqynpxMH9lAdjFRt1sIwlogFCztk9O7RK1o50TJbXQOooEli8VWq7ur0CBhX218t tCraARMPM2dUxKn9fvRZFHI0GPY27m5JMeAxYtjUFHs4hETO7qhpSOlQ2X/+25gj1T Ys41JWchsdvvkRldwU1pzCvx7aNpPFbQ22EqE0yjuAy6eceOvH9HcD/7W2czE7RDBU kRbhCThuxy+oA== Received: from johan by xi.lan with local (Exim 4.93.0.4) (envelope-from ) id 1lGeUY-0006pJ-5i; Mon, 01 Mar 2021 10:05:26 +0100 From: Johan Hovold To: Linus Walleij , Bartosz Golaszewski Cc: Greg Kroah-Hartman , Saravana Kannan , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , syzbot+d27b4c8adbbff70fbfde@syzkaller.appspotmail.com Subject: [PATCH v2 1/2] gpio: fix NULL-deref-on-deregistration regression Date: Mon, 1 Mar 2021 10:05:18 +0100 Message-Id: <20210301090519.26192-2-johan@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210301090519.26192-1-johan@kernel.org> References: <20210301090519.26192-1-johan@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Fix a NULL-pointer deference when deregistering the gpio character device that was introduced by the recent stub-driver hack. When the new "driver" is unbound as part of deregistration, driver core clears the driver-data pointer which is used to retrieve the struct gpio_device in its release callback. Fix this by using container_of() in the release callback as should have been done all along. Fixes: 4731210c09f5 ("gpiolib: Bind gpio_device to a driver to enable fw_devlink=on by default") Cc: Saravana Kannan Cc: Greg Kroah-Hartman Reported-by: syzbot+d27b4c8adbbff70fbfde@syzkaller.appspotmail.com Signed-off-by: Johan Hovold Reviewed-by: Linus Walleij --- drivers/gpio/gpiolib.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index adf55db080d8..6e0572515d02 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -474,7 +474,7 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid); static void gpiodevice_release(struct device *dev) { - struct gpio_device *gdev = dev_get_drvdata(dev); + struct gpio_device *gdev = container_of(dev, struct gpio_device, dev); list_del(&gdev->list); ida_free(&gpio_ida, gdev->id); @@ -605,7 +605,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, goto err_free_ida; device_initialize(&gdev->dev); - dev_set_drvdata(&gdev->dev, gdev); if (gc->parent && gc->parent->driver) gdev->owner = gc->parent->driver->owner; else if (gc->owner)