[PATCH 4.19 19/88] dmaengine: at_hdmac: check return value of of_find_device_by_node() in at_dma_xlate()

[Greg Kroah-Hartman]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

[ Upstream commit 0cef8e2c5a07d482ec907249dbd6687e8697677f ]

The reurn value of of_find_device_by_node() is not checked, thus null
pointer dereference will be triggered if of_find_device_by_node()
failed.

Fixes: bbe89c8e3d59 ("at_hdmac: move to generic DMA binding")
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200817115728.1706719-2-yukuai3@xxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/dma/at_hdmac.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index dbc51154f1229..86427f6ba78cb 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1677,6 +1677,8 @@ static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
 		return NULL;
 
 	dmac_pdev = of_find_device_by_node(dma_spec->np);
+	if (!dmac_pdev)
+		return NULL;
 
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_SLAVE, mask);
-- 
2.25.1