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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 388A2C433EF for ; Sun, 17 Oct 2021 15:48:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0182260F36 for ; Sun, 17 Oct 2021 15:48:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238213AbhJQPuh (ORCPT ); Sun, 17 Oct 2021 11:50:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:32930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237507AbhJQPuh (ORCPT ); Sun, 17 Oct 2021 11:50:37 -0400 Received: from jic23-huawei (cpc108967-cmbg20-2-0-cust86.5-4.cable.virginm.net [81.101.6.87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3E40461038; Sun, 17 Oct 2021 15:48:26 +0000 (UTC) Date: Sun, 17 Oct 2021 16:52:40 +0100 From: Jonathan Cameron To: Yang Yingliang Cc: , , , Subject: Re: [PATCH] iio: core: check return value when calling dev_set_name() Message-ID: <20211017165240.56fdc296@jic23-huawei> In-Reply-To: <20211012063624.3167460-1-yangyingliang@huawei.com> References: <20211012063624.3167460-1-yangyingliang@huawei.com> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Tue, 12 Oct 2021 14:36:24 +0800 Yang Yingliang wrote: > I got a null-ptr-deref report when doing fault injection test: > > BUG: kernel NULL pointer dereference, address: 0000000000000000 > RIP: 0010:strlen+0x0/0x20 > Call Trace: > start_creating+0x199/0x2f0 > debugfs_create_dir+0x25/0x430 > __iio_device_register+0x4da/0x1b40 [industrialio] > __devm_iio_device_register+0x22/0x80 [industrialio] > max1027_probe+0x639/0x860 [max1027] > spi_probe+0x183/0x210 > really_probe+0x285/0xc30 > > If dev_set_name() fails, the dev_name() is null, check the return > value of dev_set_name() to avoid the null-ptr-deref. > > Reported-by: Hulk Robot > Fixes: e553f182d55b ("staging: iio: core: Introduce debugfs support...") > Signed-off-by: Yang Yingliang Hi Yang Yingliang, I've been delaying replying to these for a few days because you have identified a more significant issue whilst working in this area and I wanted to take a deeper look at it. After we call device_initialize() a few lines above this all the cleanup on error should be done via a put_device() call, not by cleaning it up manually. However, that's clearly a much more substantial change so I'm going to apply this for now and deal with that cleanup at a later date. Thanks, Jonathan > --- > drivers/iio/industrialio-core.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c > index 2dc837db50f7..3e1e86d987cc 100644 > --- a/drivers/iio/industrialio-core.c > +++ b/drivers/iio/industrialio-core.c > @@ -1665,7 +1665,13 @@ struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv) > kfree(iio_dev_opaque); > return NULL; > } > - dev_set_name(&indio_dev->dev, "iio:device%d", iio_dev_opaque->id); > + > + if (dev_set_name(&indio_dev->dev, "iio:device%d", iio_dev_opaque->id)) { > + ida_simple_remove(&iio_ida, iio_dev_opaque->id); > + kfree(iio_dev_opaque); > + return NULL; > + } > + > INIT_LIST_HEAD(&iio_dev_opaque->buffer_list); > INIT_LIST_HEAD(&iio_dev_opaque->ioctl_handlers); >