[PATCH 5.6 053/194] dmaengine: pch_dma.c: Avoid data race between probe and irq handler

Greg Kroah-Hartman
2020-05-18T18:01:54Z

From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

[ Upstream commit 2e45676a4d33af47259fa186ea039122ce263ba9 ]

pd->dma.dev is read in irq handler pd_irq().
However, it is set to pdev->dev after request_irq().
Therefore, set pd->dma.dev to pdev->dev before request_irq() to
avoid data race between pch_dma_probe() and pd_irq().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Link: https://lore.kernel.org/r/20200416062335.29223-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/pch_dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/pch_dma.c b/drivers/dma/pch_dma.c
index 581e7a290d98e..a3b0b4c56a190 100644
--- a/drivers/dma/pch_dma.c
+++ b/drivers/dma/pch_dma.c
@@ -865,6 +865,7 @@ static int pch_dma_probe(struct pci_dev *pdev,
}

pci_set_master(pdev);
+ pd->dma.dev = &pdev->dev;

err = request_irq(pdev->irq, pd_irq, IRQF_SHARED, DRV_NAME, pd);
if (err) {
@@ -880,7 +881,6 @@ static int pch_dma_probe(struct pci_dev *pdev,
goto err_free_irq;
}

- pd->dma.dev = &pdev->dev;

INIT_LIST_HEAD(&pd->dma.channels);

--
2.20.1