4.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
commit 95264c8c6a9040e84edda883dbbe9d193c41f46c upstream.
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@xxxxxxxxx>
Fixes: 6572389bcc11 ("staging: iio: cdc: ad7152: Implement IIO_CHAN_INFO_SAMP_FREQ attribute")
Acked-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/iio/cdc/ad7152.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
--- 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(st
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;
}