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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yu Kuai <yukuai3@huawei.com>,
        Vinod Koul <vkoul@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 12/71] dmaengine: at_hdmac: check return value of of_find_device_by_node() in at_dma_xlate()
Date:   Fri, 11 Sep 2020 14:45:56 +0200
Message-Id: <20200911122505.554791505@linuxfoundation.org>
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From: Yu Kuai <yukuai3@huawei.com>

[ 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>
---
 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 a32cd71f94bbe..cb72b8c915c73 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1810,6 +1810,8 @@ 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