iio: adc: xilinx: fix potential use-after-free on remove

When cancel_delayed_work() returns, the delayed work may still
be running. This means that the core could potentially free
the private structure (struct xadc) while the delayed work
is still using it. This is a potential use-after-free.

Fix by calling cancel_delayed_work_sync(), which waits for
any residual work to finish before returning.

Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c
index b13c615..ef3afae 100644 (file)
--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -1322,7 +1322,7 @@ static int xadc_remove(struct platform_device *pdev)
        }
        free_irq(xadc->irq, indio_dev);
        clk_disable_unprepare(xadc->clk);
-       cancel_delayed_work(&xadc->zynq_unmask_work);
+       cancel_delayed_work_sync(&xadc->zynq_unmask_work);
        kfree(xadc->data);
        kfree(indio_dev->channels);