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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Sven Van Asbroeck <TheSven73@gmail.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 3.18 65/86] iio: adc: xilinx: fix potential use-after-free on remove
Date:   Wed, 15 May 2019 12:55:42 +0200
Message-Id: <20190515090654.643286016@linuxfoundation.org>
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[ 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@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 a483747cdc9b9..b520de11fc17f 100644
--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -1315,7 +1315,7 @@ static int xadc_remove(struct platform_device *pdev)
 	}
 	free_irq(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