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Date:   Mon, 2 Oct 2023 10:17:42 +0100
From:   Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To:     Dan Carpenter <dan.carpenter@linaro.org>
CC:     David Lechner <dlechner@baylibre.com>, <linux-iio@vger.kernel.org>,
        <devicetree@vger.kernel.org>, <linux-staging@lists.linux.dev>,
        David Lechner <david@lechnology.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Michael Hennerich <Michael.Hennerich@analog.com>,
        Nuno =?ISO-8859-1?Q?S?= =?ISO-8859-1?Q?=E1?= 
        <nuno.sa@analog.com>, Axel Haslam <ahaslam@baylibre.com>,
        Philip Molloy <pmolloy@baylibre.com>,
        <linux-kernel@vger.kernel.org>,
        Vincent Whitchurch <vincent.whitchurch@axis.com>
Subject: Re: [PATCH v3 02/27] staging: iio: resolver: ad2s1210: fix use
 before initialization
Message-ID: <20231002101742.0000774b@Huawei.com>
In-Reply-To: <1b366292-6e05-421e-914e-6d3457886238@kadam.mountain>
References: <20230929-ad2s1210-mainline-v3-0-fa4364281745@baylibre.com>
        <20230929-ad2s1210-mainline-v3-2-fa4364281745@baylibre.com>
        <1b366292-6e05-421e-914e-6d3457886238@kadam.mountain>
Organization: Huawei Technologies Research and Development (UK) Ltd.
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On Mon, 2 Oct 2023 11:07:15 +0300
Dan Carpenter <dan.carpenter@linaro.org> wrote:

> On Fri, Sep 29, 2023 at 12:23:07PM -0500, David Lechner wrote:
> > From: David Lechner <david@lechnology.com>
> > 
> > From: David Lechner <dlechner@baylibre.com>
> > 
> > This fixes a use before initialization in ad2s1210_probe(). The
> > ad2s1210_setup_gpios() function uses st->sdev but it was being called
> > before this field was initialized.
> > 
> > Signed-off-by: David Lechner <dlechner@baylibre.com>
> > ---
> >   
> 
> Fixes: b19e9ad5e2cb ("staging:iio:resolver:ad2s1210 general driver cleanup.")
Thanks but nope, not that one.

At that point ad2s1210_setup_gpios, didn't use st->sdev.
I think this went wrong when the platform data was removed in 

I 'think' it was
Fixes: f356dc6ec26b ("staging: iio: ad2s1210: Switch to the gpio descriptor interface")


> 
> This would crash the driver right away, on probe.  It's amazing no one
> filed a bug report even though the bug is 12 years old.
Only 5 years :)

Welcome to the long tail of IIO Devices and the long term availability of the
hardware - this is still a production part.  Clearly no one was using the
upstream driver for 5 + years, but here comes David who is not only fixing
the bugs but cleaning it up.

Hmm. What happened to roadtest? I was hoping that would solve this sort
of issue by allowing simple testing of basic functionality... Hope it
is still headed for a new version / upstream!

Jonathan

> regards,
> dan carpenter