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SubjectRe: [PATCH] staging: iio: ad7152: Fix deadlock in ad7152_write_raw_samp_freq()
On Sun, 28 May 2017 11:47:04 +0200
Lars-Peter Clausen <lars@metafoo.de> wrote:

> On 05/27/2017 12:53 AM, Alexey Khoroshilov wrote:
> > ad7152_write_raw_samp_freq() is called by ad7152_write_raw() with
> > chip->state_lock held. So, there is unavoidable deadlock when
> > ad7152_write_raw_samp_freq() locks the mutex itself.
> >
> > The patch removes unneeded locking.
> >
> > Found by Linux Driver Verification project (linuxtesting.org).
> >
> > Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
>
> Looks good, thanks.
>
> Fixes: 6572389bcc11 ("staging: iio: cdc: ad7152: Implement
> IIO_CHAN_INFO_SAMP_FREQ attribute")
> Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Applied to the fixes-togreg branch of iio.git.

Thanks,

Jonathan
>
>
> > ---
> > drivers/staging/iio/cdc/ad7152.c | 6 +-----
> > 1 file changed, 1 insertion(+), 5 deletions(-)
> >
> > diff --git a/drivers/staging/iio/cdc/ad7152.c b/drivers/staging/iio/cdc/ad7152.c
> > index dc6ecd824365..ff10d1f0a7e4 100644
> > --- a/drivers/staging/iio/cdc/ad7152.c
> > +++ b/drivers/staging/iio/cdc/ad7152.c
> > @@ -231,16 +231,12 @@ static int ad7152_write_raw_samp_freq(struct device *dev, int val)
> > if (i >= ARRAY_SIZE(ad7152_filter_rate_table))
> > i = ARRAY_SIZE(ad7152_filter_rate_table) - 1;
> >
> > - mutex_lock(&chip->state_lock);
> > ret = i2c_smbus_write_byte_data(chip->client,
> > AD7152_REG_CFG2, AD7152_CFG2_OSR(i));
> > - if (ret < 0) {
> > - mutex_unlock(&chip->state_lock);
> > + if (ret < 0)
> > return ret;
> > - }
> >
> > chip->filter_rate_setup = i;
> > - mutex_unlock(&chip->state_lock);
> >
> > return ret;
> > }
> >
>
> --
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