[PATCH 4.19 009/113] iio: adc: xilinx: fix potential use-after-free on remove

From: Greg Kroah-Hartman
Date: Wed May 15 2019 - 07:24:31 EST


[ Upstream commit 62039b6aef63380ba7a37c113bbaeee8a55c5342 ]

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@xxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/iio/adc/xilinx-xadc-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c
index 3f6be5ac049a8..1960694e80076 100644
--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -1320,7 +1320,7 @@ 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);

--
2.20.1