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Subject[PATCH 5.4 044/132] drivers/dma/dma-jz4780: Fix race condition between probe and irq handler
Date
From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

[ Upstream commit 6d6018fc30bee67290dbed2fa51123f7c6f3d691 ]

In probe, IRQ is requested before zchan->id is initialized which can be
read in the irq handler. Hence, shift request irq after other initializations
complete.

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

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20200821034423.12713-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/dma-jz4780.c | 38 +++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c
index bf95f1d551c51..0ecb724b394f5 100644
--- a/drivers/dma/dma-jz4780.c
+++ b/drivers/dma/dma-jz4780.c
@@ -885,24 +885,11 @@ static int jz4780_dma_probe(struct platform_device *pdev)
return -EINVAL;
}

- ret = platform_get_irq(pdev, 0);
- if (ret < 0)
- return ret;
-
- jzdma->irq = ret;
-
- ret = request_irq(jzdma->irq, jz4780_dma_irq_handler, 0, dev_name(dev),
- jzdma);
- if (ret) {
- dev_err(dev, "failed to request IRQ %u!\n", jzdma->irq);
- return ret;
- }
-
jzdma->clk = devm_clk_get(dev, NULL);
if (IS_ERR(jzdma->clk)) {
dev_err(dev, "failed to get clock\n");
ret = PTR_ERR(jzdma->clk);
- goto err_free_irq;
+ return ret;
}

clk_prepare_enable(jzdma->clk);
@@ -955,10 +942,23 @@ static int jz4780_dma_probe(struct platform_device *pdev)
jzchan->vchan.desc_free = jz4780_dma_desc_free;
}

+ ret = platform_get_irq(pdev, 0);
+ if (ret < 0)
+ goto err_disable_clk;
+
+ jzdma->irq = ret;
+
+ ret = request_irq(jzdma->irq, jz4780_dma_irq_handler, 0, dev_name(dev),
+ jzdma);
+ if (ret) {
+ dev_err(dev, "failed to request IRQ %u!\n", jzdma->irq);
+ goto err_disable_clk;
+ }
+
ret = dmaenginem_async_device_register(dd);
if (ret) {
dev_err(dev, "failed to register device\n");
- goto err_disable_clk;
+ goto err_free_irq;
}

/* Register with OF DMA helpers. */
@@ -966,17 +966,17 @@ static int jz4780_dma_probe(struct platform_device *pdev)
jzdma);
if (ret) {
dev_err(dev, "failed to register OF DMA controller\n");
- goto err_disable_clk;
+ goto err_free_irq;
}

dev_info(dev, "JZ4780 DMA controller initialised\n");
return 0;

-err_disable_clk:
- clk_disable_unprepare(jzdma->clk);
-
err_free_irq:
free_irq(jzdma->irq, jzdma);
+
+err_disable_clk:
+ clk_disable_unprepare(jzdma->clk);
return ret;
}

--
2.25.1


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