From: William Breathitt Gray Date: Thu, 6 Apr 2023 14:40:11 +0000 (-0400) Subject: iio: addac: stx104: Fix race condition when converting analog-to-digital X-Git-Tag: v6.2.15~605 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4167e839b5475a597cc2e96fcefca59d229bad5b;p=thirdparty%2Fkernel%2Fstable.git iio: addac: stx104: Fix race condition when converting analog-to-digital commit 4f9b80aefb9e2f542a49d9ec087cf5919730e1dd upstream. The ADC conversion procedure requires several device I/O operations performed in a particular sequence. If stx104_read_raw() is called concurrently, the ADC conversion procedure could be clobbered. Prevent such a race condition by utilizing a mutex. Fixes: 4075a283ae83 ("iio: stx104: Add IIO support for the ADC channels") Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/2ae5e40eed5006ca735e4c12181a9ff5ced65547.1680790580.git.william.gray@linaro.org Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/iio/addac/stx104.c b/drivers/iio/addac/stx104.c index 48a91a95e597b..46b46b7a3c8de 100644 --- a/drivers/iio/addac/stx104.c +++ b/drivers/iio/addac/stx104.c @@ -114,6 +114,8 @@ static int stx104_read_raw(struct iio_dev *indio_dev, return IIO_VAL_INT; } + mutex_lock(&priv->lock); + /* select ADC channel */ iowrite8(chan->channel | (chan->channel << 4), ®->achan); @@ -124,6 +126,8 @@ static int stx104_read_raw(struct iio_dev *indio_dev, while (ioread8(®->cir_asr) & BIT(7)); *val = ioread16(®->ssr_ad); + + mutex_unlock(&priv->lock); return IIO_VAL_INT; case IIO_CHAN_INFO_OFFSET: /* get ADC bipolar/unipolar configuration */