Re: [PATCH v2] drivers/dma/dma-jz4780: Fix race condition between probe and irq handler
From: Paul Cercueil <paul@crapouillou.net>
Date: 2020-08-21 17:03:59
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Le ven. 21 août 2020 à 9:14, madhuparnabhowmik10@gmail.com a écrit :
From: Madhuparna Bhowmik <redacted> 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 <redacted>
Reviewed-by: Paul Cercueil <paul@crapouillou.net> Thanks for the patch. Cheers, -Paul
quoted hunk ↗ jump to hunk
--- Changes since v1: Keep enable clock before request IRQ. --- 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 448f663da89c..8beed91428bd 100644 --- a/drivers/dma/dma-jz4780.c +++ b/drivers/dma/dma-jz4780.c@@ -879,24 +879,11 @@ static int jz4780_dma_probe(structplatform_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);@@ -949,10 +936,23 @@ static int jz4780_dma_probe(structplatform_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. */@@ -960,17 +960,17 @@ static int jz4780_dma_probe(structplatform_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; } -- 2.17.1