iio: buffer: check if a buffer has been set up when poll is called

If no iio buffer has been set up and poll is called return 0.
Without this check there will be a null pointer dereference when
calling poll on a iio driver without an iio buffer.

Cc: stable@vger.kernel.org
Signed-off-by: Stefan Windfeldt-Prytz <stefan.windfeldt@axis.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index eda2a0f1658fb0996a88c410bbe9cdda0d0202d9..c7499c8bd69f19c39cbc1b4494f35eaff6c51c01 100644 (file)
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -175,7 +175,7 @@ unsigned int iio_buffer_poll(struct file *filp,
        struct iio_dev *indio_dev = filp->private_data;
        struct iio_buffer *rb = indio_dev->buffer;
 
-       if (!indio_dev->info)
+       if (!indio_dev->info || rb == NULL)
                return 0;
 
        poll_wait(filp, &rb->pollq, wait);