[PATCH 4.14 23/54] iio: buffer: check if a buffer has been set up when poll is called

From: Greg Kroah-Hartman
Date: Mon Feb 26 2018 - 15:52:55 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Stefan Windfeldt-Prytz <stefan.windfeldt@xxxxxxxx>

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@xxxxxxxxxxxxxxx
Signed-off-by: Stefan Windfeldt-Prytz <stefan.windfeldt@xxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/iio/industrialio-buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -175,7 +175,7 @@ unsigned int iio_buffer_poll(struct file
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);