iio: Fix scan mask selection

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>

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index cd5bfe3..dadd921 100644 (file)
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -320,9 +320,8 @@ static int iio_scan_mask_set(struct iio_dev *indio_dev,
        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) {