linux-kernel - [PATCH 1/7] dmaengine: sprd: Fix the possible crash when getting engine status

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Date:   Mon, 15 Apr 2019 20:14:55 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     dan.j.williams@...el.com, vkoul@...nel.org
Cc:     eric.long@...soc.com, orsonzhai@...il.com, zhang.lyra@...il.com,
        broonie@...nel.org, baolin.wang@...aro.org,
        dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/7] dmaengine: sprd: Fix the possible crash when getting engine status

We will get a NULL virtual descriptor by vchan_find_desc() when the descriptor
has been submitted, that will crash the kernel when getting the engine status.

In this case, since the descriptor has been submitted, which means the pointer
'schan->cur_desc' will point to the current descriptor, then we can use
'schan->cur_desc' to get the engine status to avoid this issue.

Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
---
 drivers/dma/sprd-dma.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index 48431e2..e29342a 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -625,7 +625,7 @@ static enum dma_status sprd_dma_tx_status(struct dma_chan *chan,
 		else
 			pos = 0;
 	} else if (schan->cur_desc && schan->cur_desc->vd.tx.cookie == cookie) {
-		struct sprd_dma_desc *sdesc = to_sprd_dma_desc(vd);
+		struct sprd_dma_desc *sdesc = schan->cur_desc;
 
 		if (sdesc->dir == DMA_DEV_TO_MEM)
 			pos = sprd_dma_get_dst_addr(schan);
-- 
1.7.9.5