Hi,
On 10/3/21 5:47 PM, Jonathan Cameron wrote:
On Sun, 8 Aug 2021 18:32:43 +0100
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
On Sat, 24 Jul 2021 16:48:40 +0100
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
On Mon, 19 Jul 2021 19:53:11 +0000
Yizhuo <yzhai003@xxxxxxx> 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@xxxxxxx>
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),
