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* [PATCH] iio: adc: stm32-dfsdm: Fix the uninitialized use if regmap_read() fails
@ 2021-07-19 19:53 Yizhuo
  2021-07-24 15:48 ` Jonathan Cameron
  0 siblings, 1 reply; 6+ messages in thread
From: Yizhuo @ 2021-07-19 19:53 UTC (permalink / raw)
  Cc: Yizhuo, Jonathan Cameron, Lars-Peter Clausen, Maxime Coquelin,
	Alexandre Torgue, Andy Shevchenko, Mark Brown,
	Mugilraj Dhavachelvan, Olivier Moysan, Krzysztof Kozlowski,
	Arnaud Pouliquen, linux-iio, linux-stm32, linux-arm-kernel,
	linux-kernel

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>
---
 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);
+	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),
-- 
2.17.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] iio: adc: stm32-dfsdm: Fix the uninitialized use if regmap_read() fails
  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
  0 siblings, 1 reply; 6+ messages in thread
From: Jonathan Cameron @ 2021-07-24 15:48 UTC (permalink / raw)
  To: Yizhuo
  Cc: Lars-Peter Clausen, Maxime Coquelin, Alexandre Torgue,
	Andy Shevchenko, Mark Brown, Mugilraj Dhavachelvan,
	Olivier Moysan, Krzysztof Kozlowski, Arnaud Pouliquen, linux-iio,
	linux-stm32, linux-arm-kernel, linux-kernel

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.

> ---
>  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),


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] iio: adc: stm32-dfsdm: Fix the uninitialized use if regmap_read() fails
  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
  0 siblings, 2 replies; 6+ messages in thread
From: Jonathan Cameron @ 2021-08-08 17:32 UTC (permalink / raw)
  To: Yizhuo
  Cc: Lars-Peter Clausen, Maxime Coquelin, Alexandre Torgue,
	Andy Shevchenko, Mark Brown, Mugilraj Dhavachelvan,
	Olivier Moysan, Krzysztof Kozlowski, Arnaud Pouliquen, linux-iio,
	linux-stm32, linux-arm-kernel, linux-kernel

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?

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),  
> 


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] iio: adc: stm32-dfsdm: Fix the uninitialized use if regmap_read() fails
  2021-08-08 17:32   ` Jonathan Cameron
@ 2021-08-09  2:36     ` Yizhuo Zhai
  2021-10-03 15:47     ` Jonathan Cameron
  1 sibling, 0 replies; 6+ messages in thread
From: Yizhuo Zhai @ 2021-08-09  2:36 UTC (permalink / raw)
  To: Jonathan Cameron
  Cc: Lars-Peter Clausen, Maxime Coquelin, Alexandre Torgue,
	Andy Shevchenko, Mark Brown, Mugilraj Dhavachelvan,
	Olivier Moysan, Krzysztof Kozlowski, Arnaud Pouliquen, linux-iio,
	linux-stm32, linux-arm-kernel, Linux Kernel Mailing List

Hi Jonathan:
Thanks for your effort, and yes please take a look just in case.
FYI, I made the modifications align with Alexandru's help, this is the
original reply:

On Mon, Jul 19, 2021 at 12:47 AM Alexandru Ardelean
<ardeleanalex@gmail.com> wrote:
>
> On Mon, Jul 19, 2021 at 2:39 AM Yizhuo Zhai <yzhai003@ucr.edu> wrote:
> >
> > Hi All:
> > 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. However,
> > stm32_dfsdm_irq() returns the type irqreturn_t and I could not return
>
> Just curious: are you seeing any issues with these variables being
> uninitialized?
>
> > the error code directly. Could you please advise me here?
>
> The correct way to do it, would be:
>
> ret = regmap_read(regmap, DFSDM_ISR(adc->fl_id), &status);
> if (ret)
>     return IRQ_HANDLED;
>
> IRQ handlers should return one of
> enum irqreturn {
>     IRQ_NONE        = (0 << 0),
>     IRQ_HANDLED     = (1 << 0),
>     IRQ_WAKE_THREAD     = (1 << 1),
> };
>
> If you want to fully optimize/correct this, then it may be something like:
>
>         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 */
>                 regmap_read(regmap, DFSDM_RDATAR(adc->fl_id), adc->buffer);
>
> // in this point, we could check for regmap_read(), but it won't make
> sense; we should call the complete() handler, either way
>
>                 complete(&adc->completion);
>         }
>
>         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),
>                                    DFSDM_ICR_CLRROVRF_MASK,
>                                    DFSDM_ICR_CLRROVRF_MASK);
>
> // in this point, we could also check the ret code; but we still need
> to call IRQ_HANDLED anyway;
>         }
>
>
> Quite often, when regmap_read() returns errors, then something is
> seriously wrong in the system.
> Something else would usually fail or crash worse than this interrupt handler.
> That being said, properly handling regmap_read() here is a good idea.
>
> >
> > The related code:
> >
> > static irqreturn_t stm32_dfsdm_irq(int irq, void *arg) {
> >     unsigned int status, int_en;
> >
> >     regmap_read(regmap, DFSDM_ISR(adc->fl_id), &status);
> >     regmap_read(regmap, DFSDM_CR2(adc->fl_id), &int_en);
> >
> >     if (status & DFSDM_ISR_REOCF_MASK) {}
> >     if (status & DFSDM_ISR_ROVRF_MASK) {}
> > }
> >
> >
> > --
> > Kind Regards,
> >
> > Yizhuo Zhai
> >
> > Computer Science, Graduate Student
> > University of California, Riverside


On Sun, Aug 8, 2021 at 10:29 AM 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?
>
> 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),
> >
>


--
Kind Regards,

Yizhuo Zhai

Computer Science, Graduate Student
University of California, Riverside

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] iio: adc: stm32-dfsdm: Fix the uninitialized use if regmap_read() fails
  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
  1 sibling, 1 reply; 6+ messages in thread
From: Jonathan Cameron @ 2021-10-03 15:47 UTC (permalink / raw)
  To: Yizhuo, Mugilraj Dhavachelvan, Olivier Moysan,
	Krzysztof Kozlowski, Arnaud Pouliquen, linux-stm32
  Cc: Lars-Peter Clausen, Maxime Coquelin, Alexandre Torgue,
	Andy Shevchenko, Mark Brown, linux-iio, linux-arm-kernel,
	linux-kernel

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

> 
> 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),    
> >   
> 


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] iio: adc: stm32-dfsdm: Fix the uninitialized use if regmap_read() fails
  2021-10-03 15:47     ` Jonathan Cameron
@ 2021-10-05  8:18       ` Olivier MOYSAN
  0 siblings, 0 replies; 6+ messages in thread
From: Olivier MOYSAN @ 2021-10-05  8:18 UTC (permalink / raw)
  To: Jonathan Cameron, Yizhuo, Mugilraj Dhavachelvan, Olivier Moysan,
	Krzysztof Kozlowski, Arnaud Pouliquen, linux-stm32
  Cc: Lars-Peter Clausen, Maxime Coquelin, Alexandre Torgue,
	Andy Shevchenko, Mark Brown, linux-iio, linux-arm-kernel,
	linux-kernel

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),
>>>    
>>
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-10-05  8:19 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
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

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