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=-15.5 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_2 autolearn=unavailable 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 53745C433E6 for ; Fri, 12 Feb 2021 19:13:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1464D60241 for ; Fri, 12 Feb 2021 19:13:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231998AbhBLTNM convert rfc822-to-8bit (ORCPT ); Fri, 12 Feb 2021 14:13:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:36264 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231978AbhBLTNG (ORCPT ); Fri, 12 Feb 2021 14:13:06 -0500 Received: from archlinux (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 57BF360241; Fri, 12 Feb 2021 19:12:23 +0000 (UTC) Date: Fri, 12 Feb 2021 19:12:19 +0000 From: Jonathan Cameron To: Petr =?UTF-8?B?xaB0ZXRpYXI=?= Cc: Tomasz Duszynski , Lars-Peter Clausen , Peter Meerwald-Stadler , stable@vger.kernel.org, Jonathan Cameron , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] iio: chemical: scd30: fix Oops due to missing parent device Message-ID: <20210212191219.7b16abbb@archlinux> In-Reply-To: <20210208223947.32344-1-ynezz@true.cz> References: <20210208223947.32344-1-ynezz@true.cz> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 8 Feb 2021 23:39:47 +0100 Petr Štetiar wrote: > My machine Oopsed while testing SCD30 sensor in interrupt driven mode: > > Unable to handle kernel NULL pointer dereference at virtual address 00000188 > pgd = (ptrval) > [00000188] *pgd=00000000 > Internal error: Oops: 5 [#1] SMP ARM > Modules linked in: > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.96+ #473 > Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree) > PC is at _raw_spin_lock_irqsave+0x10/0x4c > LR is at devres_add+0x18/0x38 > ... > [<8070ecac>] (_raw_spin_lock_irqsave) from [<804916a8>] (devres_add+0x18/0x38) > [<804916a8>] (devres_add) from [<805ef708>] (devm_iio_trigger_alloc+0x5c/0x7c) > [<805ef708>] (devm_iio_trigger_alloc) from [<805f0a90>] (scd30_probe+0x1d4/0x3f0) > [<805f0a90>] (scd30_probe) from [<805f10fc>] (scd30_i2c_probe+0x54/0x64) > [<805f10fc>] (scd30_i2c_probe) from [<80583390>] (i2c_device_probe+0x150/0x278) > [<80583390>] (i2c_device_probe) from [<8048e6c0>] (really_probe+0x1f8/0x360) > > I've found out, that it's due to missing parent/owner device in iio_dev struct > which then leads to NULL pointer dereference during spinlock while registering > the device resource via devres_add(). > > Cc: # v5.9+ > Fixes: 64b3d8b1b0f5 ("iio: chemical: scd30: add core driver") > Signed-off-by: Petr Štetiar Hi Petr, So, we moved this into the core a while back (to avoid exactly this sort of issue). That change predates this introduction of this driver as it went in in v5.8 So I think you've hit an issue with a backport here to an earlier kernel? Jonathan > --- > drivers/iio/chemical/scd30_core.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/iio/chemical/scd30_core.c b/drivers/iio/chemical/scd30_core.c > index 4d0d798c7cd3..33aa6eb1963d 100644 > --- a/drivers/iio/chemical/scd30_core.c > +++ b/drivers/iio/chemical/scd30_core.c > @@ -697,6 +697,7 @@ int scd30_probe(struct device *dev, int irq, const char *name, void *priv, > > dev_set_drvdata(dev, indio_dev); > > + indio_dev->dev.parent = dev; > indio_dev->info = &scd30_info; > indio_dev->name = name; > indio_dev->channels = scd30_channels;