[PATCH 3.16 005/157] iio: Fix scan mask selection

From: Ben Hutchings
Date: Sat Aug 10 2019 - 16:51:50 EST

3.16.72-rc1 review patch. If anyone has any objections, please let me know.


From: Lars-Peter Clausen <lars@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
Fixes commit 057ac1acdfc4 ("iio: Use kmalloc_array() in iio_scan_mask_set()").
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
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
@@ -836,9 +836,8 @@ int iio_scan_mask_set(struct iio_dev *in
const unsigned long *mask;
unsigned long *trialmask;

- trialmask = kmalloc_array(BITS_TO_LONGS(indio_dev->masklength),
- sizeof(*trialmask),
+ trialmask = kcalloc(BITS_TO_LONGS(indio_dev->masklength),
+ sizeof(*trialmask), GFP_KERNEL);
if (trialmask == NULL)
return -ENOMEM;
if (!indio_dev->masklength) {