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From:   Jia-Ju Bai <baijiaju1990@gmail.com>
To:     vkoul@kernel.org, dan.j.williams@intel.com,
        mcoquelin.stm32@gmail.com, alexandre.torgue@st.com
Cc:     dmaengine@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH] dma: stm32-mdma: Fix a possible null-pointer dereference in stm32_mdma_irq_handler()
Date:   Mon, 29 Jul 2019 10:08:49 +0800
Message-Id: <20190729020849.17971-1-baijiaju1990@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In stm32_mdma_irq_handler(), chan is checked on line 1368.
When chan is NULL, it is still used on line 1369:
    dev_err(chan2dev(chan), "MDMA channel not initialized\n");

Thus, a possible null-pointer dereference may occur.

To fix this bug, "dev_dbg(mdma2dev(dmadev), ...)" is used instead.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 drivers/dma/stm32-mdma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index d6e919d3936a..1311de74bfdd 100644
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -1366,7 +1366,7 @@ static irqreturn_t stm32_mdma_irq_handler(int irq, void *devid)
 
 	chan = &dmadev->chan[id];
 	if (!chan) {
-		dev_err(chan2dev(chan), "MDMA channel not initialized\n");
+		dev_dbg(mdma2dev(dmadev), "MDMA channel not initialized\n");
 		goto exit;
 	}
 
-- 
2.17.0