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Message-Id: <1495839184-28468-1-git-send-email-khoroshilov@ispras.ru>
Date: Sat, 27 May 2017 01:53:04 +0300
From: Alexey Khoroshilov <khoroshilov@...ras.ru>
To: Lars-Peter Clausen <lars@...afoo.de>,
Michael Hennerich <Michael.Hennerich@...log.com>,
Jonathan Cameron <jic23@...nel.org>,
Hartmut Knaack <knaack.h@....de>,
Peter Meerwald-Stadler <pmeerw@...erw.net>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Alexey Khoroshilov <khoroshilov@...ras.ru>,
linux-iio@...r.kernel.org, devel@...verdev.osuosl.org,
linux-kernel@...r.kernel.org, ldv-project@...uxtesting.org
Subject: [PATCH] staging: iio: ad7152: Fix deadlock in ad7152_write_raw_samp_freq()
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@...ras.ru>
---
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;
}
--
2.7.4
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