Patch "staging: iio: ad7152: Fix deadlock in ad7152_write_raw_samp_freq()" has been added to the 4.11-stable tree

This is a note to let you know that I've just added the patch titled

    staging: iio: ad7152: Fix deadlock in ad7152_write_raw_samp_freq()

to the 4.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     staging-iio-ad7152-fix-deadlock-in-ad7152_write_raw_samp_freq.patch

and it can be found in the queue-4.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Alexey Khoroshilov <[email protected]>
Date: Sat, 27 May 2017 01:53:04 +0300
Subject: staging: iio: ad7152: Fix deadlock in ad7152_write_raw_samp_freq()

From: Alexey Khoroshilov <[email protected]>

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).

---
 drivers/staging/iio/cdc/ad7152.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

@@ -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;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.11/staging-iio-ad7152-fix-deadlock-in-ad7152_write_raw_samp_freq.patch