iio: proximity: as3935: fix buffer stack trashing

Buffer wasn't of a valid size to allow the timestamp, and correct padding.
This patchset also moves the buffer off the stack, and onto the heap.

Cc: george.mccollister@gmail.com
Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/iio/proximity/as3935.c b/drivers/iio/proximity/as3935.c
index 6aed02437efc..e2f926cdcad2 100644
--- a/drivers/iio/proximity/as3935.c
+++ b/drivers/iio/proximity/as3935.c
@@ -64,6 +64,7 @@ struct as3935_state {
         struct delayed_work work;
 
         u32 tune_cap;
+        u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
         u8 buf[2] ____cacheline_aligned;
 };
 
@@ -212,9 +213,10 @@ static irqreturn_t as3935_trigger_handler(int irq, void *private)
         ret = as3935_read(st, AS3935_DATA, &val);
         if (ret)
                 goto err_read;
-        val &= AS3935_DATA_MASK;
 
-        iio_push_to_buffers_with_timestamp(indio_dev, &val, pf->timestamp);
+        st->buffer[0] = val & AS3935_DATA_MASK;
+        iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
+                                           pf->timestamp);
 err_read:
         iio_trigger_notify_done(indio_dev->trig);