dmaengine: at_hdmac: check return value of of_find_device_by_node() in at_dma_xlate()

[ 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@huawei.com>
Link: https://lore.kernel.org/r/20200817115728.1706719-2-yukuai3@huawei.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 672c73b4a2d4fb3c852e40ceeae0d5cd7ae97c0c..ff366c2f58c18a8d6966bc4983e48a3349a64ff5 100644 (file)
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1667,6 +1667,8 @@ 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);