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

commit 4cd140bda6494543f1c1b0ccceceaa44b676eef6 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 158aaf4..5d05c38 100644 (file)
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -174,7 +174,7 @@ 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);