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

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Message-Id: <20200507142917.26612-9-sashal@kernel.org>
Date:   Thu,  7 May 2020 10:29:05 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Madhuparna Bhowmik <madhuparnabhowmik10@...il.com>,
        Vinod Koul <vkoul@...nel.org>, Sasha Levin <sashal@...nel.org>,
        dmaengine@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 09/20] dmaengine: pch_dma.c: Avoid data race between probe and irq handler

From: Madhuparna Bhowmik <madhuparnabhowmik10@...il.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@...il.com>
Link: https://lore.kernel.org/r/20200416062335.29223-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.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 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