From: Olivier MOYSAN <olivier.moysan@foss.st.com>
To: Jonathan Cameron <jic23@kernel.org>, Yizhuo <yzhai003@ucr.edu>,
"Mugilraj Dhavachelvan" <dmugil2000@gmail.com>,
Olivier Moysan <olivier.moysan@st.com>,
Krzysztof Kozlowski <krzk@kernel.org>,
Arnaud Pouliquen <arnaud.pouliquen@st.com>,
<linux-stm32@st-md-mailman.stormreply.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Mark Brown <broonie@kernel.org>, <linux-iio@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] iio: adc: stm32-dfsdm: Fix the uninitialized use if regmap_read() fails
Date: Tue, 5 Oct 2021 10:18:33 +0200 [thread overview]
Message-ID: <9d8d6633-deba-bcf8-f717-68def3ef798e@foss.st.com> (raw)
In-Reply-To: <20211003164726.42e20526@jic23-huawei>
Hi,
On 10/3/21 5:47 PM, Jonathan Cameron wrote:
> On Sun, 8 Aug 2021 18:32:43 +0100
> Jonathan Cameron <jic23@kernel.org> wrote:
>
>> On Sat, 24 Jul 2021 16:48:40 +0100
>> Jonathan Cameron <jic23@kernel.org> wrote:
>>
>>> On Mon, 19 Jul 2021 19:53:11 +0000
>>> Yizhuo <yzhai003@ucr.edu> wrote:
>>>
>>>> Inside function stm32_dfsdm_irq(), the variable "status", "int_en"
>>>> could be uninitialized if the regmap_read() fails and returns an error
>>>> code. However, they are directly used in the later context to decide
>>>> the control flow, which is potentially unsafe.
>>>>
>>>> Fixes: e2e6771c64625 ("IIO: ADC: add STM32 DFSDM sigma delta ADC support")
>>>>
>>>> Signed-off-by: Yizhuo <yzhai003@ucr.edu>
>>>
>>> Hi Yizhou
>>>
>>> I want to get some review of this from people familiar with the
>>> hardware as there is a small possibility your reordering might have
>>> introduced a problem.
>>
>> To stm32 people, can someone take a look at this?
>
> This one is still outstanding. If anyone from stm32 side of things could take a look
> that would be great,
>
> Jonathan
>
I cannot see side effects with reordering itself.
However, if we get an error with the read access, just leaving with
irq_handled status is probably not enough.
In such case we are facing a serious issue and it would make sense to
return irq_none instead, as the interrupt will probably never be
acknowledged.
BRs
>>
>> Thanks,
>>
>> Jonathan
>>
>>>
>>>> ---
>>>> drivers/iio/adc/stm32-dfsdm-adc.c | 9 +++++++--
>>>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
>>>> index 1cfefb3b5e56..d8b78aead942 100644
>>>> --- a/drivers/iio/adc/stm32-dfsdm-adc.c
>>>> +++ b/drivers/iio/adc/stm32-dfsdm-adc.c
>>>> @@ -1292,9 +1292,11 @@ static irqreturn_t stm32_dfsdm_irq(int irq, void *arg)
>>>> struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
>>>> struct regmap *regmap = adc->dfsdm->regmap;
>>>> unsigned int status, int_en;
>>>> + int ret;
>>>>
>>>> - regmap_read(regmap, DFSDM_ISR(adc->fl_id), &status);
>>>> - regmap_read(regmap, DFSDM_CR2(adc->fl_id), &int_en);
>>>
>>> Moving this later is only valid if there aren't any side effects.
>>> The current ordering is strange enough it makes me wonder if there might be!
>>>
>>> Jonathan
>>>
>>>> + ret = regmap_read(regmap, DFSDM_ISR(adc->fl_id), &status);
>>>> + if (ret)
>>>> + return IRQ_HANDLED;
>>>>
>>>> if (status & DFSDM_ISR_REOCF_MASK) {
>>>> /* Read the data register clean the IRQ status */
>>>> @@ -1303,6 +1305,9 @@ static irqreturn_t stm32_dfsdm_irq(int irq, void *arg)
>>>> }
>>>>
>>>> if (status & DFSDM_ISR_ROVRF_MASK) {
>>>> + ret = regmap_read(regmap, DFSDM_CR2(adc->fl_id), &int_en);
>>>> + if (ret)
>>>> + return IRQ_HANDLED;
>>>> if (int_en & DFSDM_CR2_ROVRIE_MASK)
>>>> dev_warn(&indio_dev->dev, "Overrun detected\n");
>>>> regmap_update_bits(regmap, DFSDM_ICR(adc->fl_id),
>>>
>>
>
prev parent reply other threads:[~2021-10-05 8:19 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 19:53 [PATCH] iio: adc: stm32-dfsdm: Fix the uninitialized use if regmap_read() fails Yizhuo
2021-07-24 15:48 ` Jonathan Cameron
2021-08-08 17:32 ` Jonathan Cameron
2021-08-09 2:36 ` Yizhuo Zhai
2021-10-03 15:47 ` Jonathan Cameron
2021-10-05 8:18 ` Olivier MOYSAN [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=9d8d6633-deba-bcf8-f717-68def3ef798e@foss.st.com \
--to=olivier.moysan@foss.st.com \
--cc=alexandre.torgue@foss.st.com \
--cc=andy.shevchenko@gmail.com \
--cc=arnaud.pouliquen@st.com \
--cc=broonie@kernel.org \
--cc=dmugil2000@gmail.com \
--cc=jic23@kernel.org \
--cc=krzk@kernel.org \
--cc=lars@metafoo.de \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-iio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-stm32@st-md-mailman.stormreply.com \
--cc=mcoquelin.stm32@gmail.com \
--cc=olivier.moysan@st.com \
--cc=yzhai003@ucr.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).