[PATCH AUTOSEL 4.19 09/20] dmaengine: pch_dma.c: Avoid data race between probe and irq handler

From: Sasha Levin
Date: Thu May 07 2020 - 10:33:50 EST


From: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>

[ 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@xxxxxxxxx>
Link: https://lore.kernel.org/r/20200416062335.29223-1-madhuparnabhowmik10@xxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 afd8f27bda969..6e91584c36770 100644
--- a/drivers/dma/pch_dma.c
+++ b/drivers/dma/pch_dma.c
@@ -873,6 +873,7 @@ 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) {
@@ -888,7 +889,6 @@ 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