dmaengine: pch_dma.c: Avoid data race between probe and irq handler

BugLink: https://bugs.launchpad.net/bugs/1879759
[ 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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/dma/pch_dma.c b/drivers/dma/pch_dma.c
index 581e7a290d98e1856cb1d0428c53b4aaee6ce518..a3b0b4c56a190b55ec242762d3766dfae506dbb9 100644 (file)
--- 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);