From patchwork Fri Feb 26 14:52:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 1444955 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=WB8CwCq8; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4DnCQV14k4z9sBJ for ; Sat, 27 Feb 2021 01:56:02 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230008AbhBZOzn (ORCPT ); Fri, 26 Feb 2021 09:55:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:52630 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229769AbhBZOzn (ORCPT ); Fri, 26 Feb 2021 09:55:43 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D360464E20; Fri, 26 Feb 2021 14:55:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614351303; bh=PhR9gkTNFpRiPjJK44jCN9ors5BE/Ib0psiXx2bqJ/4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WB8CwCq8x5mC1s6JOqAuDy8bLQeaYfuztxMoZI8I6uWoN5zzI5fMvbBsiOfMjeorL GSby4P4S3SNzU36de3iQE+2oUqU3XMSTK1j0qXd/xPaAl9EVSD6YYAMct9OKbioFe1 iQD41d6ORw9EtuCee44k6Q6TM/jspZWXwo3kkYkj/6pZLpBKJxW8yPiDy4XEdPcj6p iDylENLoylWRbwEBVYRoy+4mKgG5BNOIYEGI4rB711a97WtGseTgKe1FkJBDFhOGRT CROIL2CgYzH5BTz9ebF06cbU53c9Voea9GtfBnKRfjk3zajdjopC2OIma3fXVPQ78s w1BLl8Pb4E0jg== Received: from johan by xi.lan with local (Exim 4.93.0.4) (envelope-from ) id 1lFeWZ-0000K1-Cl; Fri, 26 Feb 2021 15:55:23 +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 1/2] gpio: fix NULL-deref-on-deregistration regression Date: Fri, 26 Feb 2021 15:52:45 +0100 Message-Id: <20210226145246.1171-2-johan@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210226145246.1171-1-johan@kernel.org> References: <20210226145246.1171-1-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 --- drivers/gpio/gpiolib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index adf55db080d8..e1016bc8cf14 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);