From: Jonathan Cameron Date: Sun, 20 Sep 2020 11:27:40 +0000 (+0100) Subject: iio:pressure:mpl3115: Force alignment of buffer X-Git-Tag: v4.4.249~7 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d8b0d52e408ca39ebbca98985f29c06fd3bb7325;p=thirdparty%2Fkernel%2Fstable.git iio:pressure:mpl3115: Force alignment of buffer commit 198cf32f0503d2ad60d320b95ef6fb8243db857f upstream. Whilst this is another case of the issue Lars reported with an array of elements of smaller than 8 bytes being passed to iio_push_to_buffers_with_timestamp(), the solution here is a bit different from the other cases and relies on __aligned working on the stack (true since 4.6?) This one is unusual. We have to do an explicit memset() each time as we are reading 3 bytes into a potential 4 byte channel which may sometimes be a 2 byte channel depending on what is enabled. As such, moving the buffer to the heap in the iio_priv structure doesn't save us much. We can't use a nice explicit structure on the stack either as the data channels have different storage sizes and are all separately controlled. Fixes: cc26ad455f57 ("iio: Add Freescale MPL3115A2 pressure / temperature sensor driver") Reported-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron Reviewed-by: Andy Shevchenko Reviewed-by: Alexandru Ardelean Cc: Peter Meerwald Cc: Link: https://lore.kernel.org/r/20200920112742.170751-7-jic23@kernel.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c index 0f5b8767ec2e6..6ed4e6902effe 100644 --- a/drivers/iio/pressure/mpl3115.c +++ b/drivers/iio/pressure/mpl3115.c @@ -139,7 +139,14 @@ static irqreturn_t mpl3115_trigger_handler(int irq, void *p) struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct mpl3115_data *data = iio_priv(indio_dev); - u8 buffer[16]; /* 32-bit channel + 16-bit channel + padding + ts */ + /* + * 32-bit channel + 16-bit channel + padding + ts + * Note that it is possible for only one of the first 2 + * channels to be enabled. If that happens, the first element + * of the buffer may be either 16 or 32-bits. As such we cannot + * use a simple structure definition to express this data layout. + */ + u8 buffer[16] __aligned(8); int ret, pos = 0; mutex_lock(&data->lock);