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Date:   Sat, 5 Nov 2022 14:45:18 +0000
From:   Jonathan Cameron <jic23@kernel.org>
To:     Matti Vaittinen <mazziesaccount@gmail.com>
Cc:     Claudiu.Beznea@microchip.com, matti.vaittinen@fi.rohmeurope.com,
        lars@metafoo.de, Michael.Hennerich@analog.com,
        cosmin.tanislav@analog.com, Eugen.Hristev@microchip.com,
        Nicolas.Ferre@microchip.com, alexandre.belloni@bootlin.com,
        bleung@chromium.org, groeck@chromium.org,
        alexandru.ardelean@analog.com, nathan@kernel.org,
        miquel.raynal@bootlin.com, linmq006@gmail.com,
        u.kleine-koenig@pengutronix.de, paul@crapouillou.net,
        mihail.chindris@analog.com, gwendal@chromium.org,
        andriy.shevchenko@linux.intel.com, linux-iio@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        chrome-platform@lists.linux.dev,
        Cosmin Tanislav <cosmin.tanislav@analog.com>
Subject: Re: [RFT PATCH v3 10/10] iio: Don't silently expect attribute types
Message-ID: <20221105144518.7fa63084@jic23-huawei>
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On Mon, 10 Oct 2022 12:36:54 +0300
Matti Vaittinen <mazziesaccount@gmail.com> wrote:

> On 10/9/22 20:38, Jonathan Cameron wrote:
> > On Thu, 6 Oct 2022 15:53:52 +0300
> > Matti Vaittinen <mazziesaccount@gmail.com> wrote:
> >   
> >> Hi Claudiu,
> >>
> >> On 10/6/22 11:35, Claudiu.Beznea@microchip.com wrote:  
> >>> On 03.10.2022 11:13, Matti Vaittinen wrote:  
> >>>> The iio_triggered_buffer_setup_ext() and the
> >>>> devm_iio_kfifo_buffer_setup_ext() were changed by
> >>>> commit 15097c7a1adc ("iio: buffer: wrap all buffer attributes into iio_dev_attr")
> >>>> to silently expect that all attributes given in buffer_attrs array are
> >>>> device-attributes. This expectation was not forced by the API - and some
> >>>> drivers did register attributes created by IIO_CONST_ATTR().
> >>>>
> >>>> When using IIO_CONST_ATTRs the added attribute "wrapping" does not copy
> >>>> the pointer to stored string constant and when the sysfs file is read the
> >>>> kernel will access to invalid location.
> >>>>
> >>>> Change the function signatures to expect an array of iio_dev_attrs to
> >>>> avoid similar errors in the future.
> >>>>
> >>>> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>  
> >>>
> >>> Tested-by: Claudiu Beznea <claudiu.beznea@microchip.com>
> >>>
> >>> on SAMA5D2
> >>>      
> >>
> >> Thanks a ton for the testing! I do _really_ appreciate it :) I am now
> >> slightly more confident regarding the fix here - and a lot more
> >> confident that we do have an actual bug (as you explained in the reply
> >> to the first RFT) :)  
> > 
> > You analysis was sound, so I've long been convinced ;)
> > 
> > Anyhow, one more coming through...
> > AD4130 v9 patch had same issue and so will also need updating with this
> > patch if it lands before yours.
> > 
> > Other than that static macro being ugly (which I can't improve on!)
> > all looks good to me, but I'll let it sit a while longer. If nothing
> > else I want to rebase the fixes-togreg tree on rc1 before putting the first
> > part of this series on top of it then letting them soak in next for
> > a few days,  
> 
> Thanks Jonathan.
> 
> Can you please ping me if you want me to rebase/rework the series? (I 
> may combine this with the kx022a-series then, but naturally not all 
> patches in the series need to be applied at once. Eg, fixes can be taken 
> in faster, kx022a part can be iterated, iterated, iterated... ;] ).

Applied the remainder of this series. As expected need to make the changes
in patch 10 to your kx022a driver and the ad4130 ADC that also crossed with
this series.

+CC Cosmin for the ad4130.  Please check the result in the
testing branch of iio.git.

Applied to the togreg branch of iio.git and pushed out initially as testing.

This is a nice hardening of the code against future mistakes.

Thanks,

Jonathan

> 
> Yours
> 	-- Matti
>