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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Lars-Peter Clausen <lars@metafoo.de>,
        Alexandru Ardelean <alexandru.ardelean@analog.com>,
        Stable@vger.kernel.org,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: [PATCH 4.19 43/96] iio: Fix scan mask selection
Date:   Wed, 24 Apr 2019 19:09:48 +0200
Message-Id: <20190424170922.790046063@linuxfoundation.org>
In-Reply-To: <20190424170919.829037226@linuxfoundation.org>
References: <20190424170919.829037226@linuxfoundation.org>
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From: Lars-Peter Clausen <lars@metafoo.de>

commit 20ea39ef9f2f911bd01c69519e7d69cfec79fde3 upstream.

The trialmask is expected to have all bits set to 0 after allocation.
Currently kmalloc_array() is used which does not zero the memory and so
random bits are set. This results in random channels being enabled when
they shouldn't. Replace kmalloc_array() with kcalloc() which has the same
interface but zeros the memory.

Note the fix is actually required earlier than the below fixes tag, but
will require a manual backport due to move from kmalloc to kmalloc_array.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Fixes commit 057ac1acdfc4 ("iio: Use kmalloc_array() in iio_scan_mask_set()").
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/iio/industrialio-buffer.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -320,9 +320,8 @@ static int iio_scan_mask_set(struct iio_
 	const unsigned long *mask;
 	unsigned long *trialmask;
 
-	trialmask = kmalloc_array(BITS_TO_LONGS(indio_dev->masklength),
-				  sizeof(*trialmask),
-				  GFP_KERNEL);
+	trialmask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
+			    sizeof(*trialmask), GFP_KERNEL);
 	if (trialmask == NULL)
 		return -ENOMEM;
 	if (!indio_dev->masklength) {