[added to the 4.1 stable tree] iio: buffer: check if a buffer has been set up when poll is called

From: Stefan Windfeldt-Prytz stefan.windfeldt@axis.com

This patch has been added to the 4.1 stable tree. If you have any objections, please let us know.

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[ Upstream commit 4cd140bda6494543f1c1b0ccceceaa44b676eef6 ]

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: Sasha Levin alexander.levin@microsoft.com --- drivers/iio/industrialio-buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index 7fa280b28ecb..ec6b26f008d9 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -150,7 +150,7 @@ 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);