* [PATCH] iio: hi8435: fix race between event enable and event generation
@ 2017-05-23 8:07 Nikita Yushchenko
2017-05-24 19:30 ` Jonathan Cameron
0 siblings, 1 reply; 3+ messages in thread
From: Nikita Yushchenko @ 2017-05-23 8:07 UTC (permalink / raw)
To: Jonathan Cameron, Hartmut Knaack, Lars-Peter Clausen,
Peter Meerwald-Stadler, Sanchayan Maity, Gregor Boirie,
Matt Ranostay
Cc: linux-iio, linux-kernel, Chris Healy, Jeff White,
Vladimir Barinov, Nikita Yushchenko
Add locking to avoid interference between reading/processing current
sence in event enable and event generation paths.
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
---
drivers/iio/adc/hi8435.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/iio/adc/hi8435.c b/drivers/iio/adc/hi8435.c
index ab59969b7c49..28fc699f00f6 100644
--- a/drivers/iio/adc/hi8435.c
+++ b/drivers/iio/adc/hi8435.c
@@ -144,6 +144,8 @@ static int hi8435_write_event_config(struct iio_dev *idev,
int ret;
u32 tmp;
+ mutex_lock(&priv->lock);
+
if (state) {
ret = hi8435_readl(priv, HI8435_SO31_0_REG, &tmp);
if (ret < 0)
@@ -157,6 +159,8 @@ static int hi8435_write_event_config(struct iio_dev *idev,
} else
priv->event_scan_mask &= ~BIT(chan->channel);
+ mutex_unlock(&priv->lock);
+
return 0;
}
@@ -449,12 +453,16 @@ static irqreturn_t hi8435_trigger_handler(int irq, void *private)
u32 val;
int ret;
+ mutex_lock(&priv->lock);
+
ret = hi8435_readl(priv, HI8435_SO31_0_REG, &val);
if (ret < 0)
goto err_read;
hi8435_iio_push_event(idev, val);
+ mutex_unlock(&priv->lock);
+
err_read:
iio_trigger_notify_done(idev->trig);
--
2.11.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] iio: hi8435: fix race between event enable and event generation
2017-05-23 8:07 [PATCH] iio: hi8435: fix race between event enable and event generation Nikita Yushchenko
@ 2017-05-24 19:30 ` Jonathan Cameron
2017-05-24 19:56 ` Nikita Yushchenko
0 siblings, 1 reply; 3+ messages in thread
From: Jonathan Cameron @ 2017-05-24 19:30 UTC (permalink / raw)
To: Nikita Yushchenko
Cc: Hartmut Knaack, Lars-Peter Clausen, Peter Meerwald-Stadler,
Sanchayan Maity, Gregor Boirie, Matt Ranostay, linux-iio,
linux-kernel, Chris Healy, Jeff White, Vladimir Barinov
On Tue, 23 May 2017 11:07:29 +0300
Nikita Yushchenko <nikita.yoush@cogentembedded.com> wrote:
> Add locking to avoid interference between reading/processing current
> sence in event enable and event generation paths.
>
> Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Make sense. Could you give a little more detail on the seriousness
of this bug? I need to assess whether we just queue it up for the
next merge window or push it forward quicker as a bug fix and
whether to mark it for stable or not.
You probably have a better idea of how much it matters than I do!
Thanks,
Jonathan
> ---
> drivers/iio/adc/hi8435.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/iio/adc/hi8435.c b/drivers/iio/adc/hi8435.c
> index ab59969b7c49..28fc699f00f6 100644
> --- a/drivers/iio/adc/hi8435.c
> +++ b/drivers/iio/adc/hi8435.c
> @@ -144,6 +144,8 @@ static int hi8435_write_event_config(struct iio_dev *idev,
> int ret;
> u32 tmp;
>
> + mutex_lock(&priv->lock);
> +
> if (state) {
> ret = hi8435_readl(priv, HI8435_SO31_0_REG, &tmp);
> if (ret < 0)
> @@ -157,6 +159,8 @@ static int hi8435_write_event_config(struct iio_dev *idev,
> } else
> priv->event_scan_mask &= ~BIT(chan->channel);
>
> + mutex_unlock(&priv->lock);
> +
> return 0;
> }
>
> @@ -449,12 +453,16 @@ static irqreturn_t hi8435_trigger_handler(int irq, void *private)
> u32 val;
> int ret;
>
> + mutex_lock(&priv->lock);
> +
> ret = hi8435_readl(priv, HI8435_SO31_0_REG, &val);
> if (ret < 0)
> goto err_read;
>
> hi8435_iio_push_event(idev, val);
>
> + mutex_unlock(&priv->lock);
> +
> err_read:
> iio_trigger_notify_done(idev->trig);
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] iio: hi8435: fix race between event enable and event generation
2017-05-24 19:30 ` Jonathan Cameron
@ 2017-05-24 19:56 ` Nikita Yushchenko
0 siblings, 0 replies; 3+ messages in thread
From: Nikita Yushchenko @ 2017-05-24 19:56 UTC (permalink / raw)
To: Jonathan Cameron
Cc: Hartmut Knaack, Lars-Peter Clausen, Peter Meerwald-Stadler,
Sanchayan Maity, Gregor Boirie, Matt Ranostay, linux-iio,
linux-kernel, Chris Healy, Jeff White, Vladimir Barinov
>> Add locking to avoid interference between reading/processing current
>> sence in event enable and event generation paths.
>>
>> Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
> Make sense. Could you give a little more detail on the seriousness
> of this bug? I need to assess whether we just queue it up for the
> next merge window or push it forward quicker as a bug fix and
> whether to mark it for stable or not.
>
> You probably have a better idea of how much it matters than I do!
Race was introduced by my previous patch, and noticed by Vladimir.
It is not in any released tree.
Possible race impact is loss of event or duplicate event.
Nikita
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-05-24 19:30 ` Jonathan Cameron
2017-05-24 19:56 ` Nikita Yushchenko
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