dmaengine: stm32-mdma: Fix a possible null-pointer dereference in stm32_mdma_irq_hand...

BugLink: https://bugs.launchpad.net/bugs/1843338
[ Upstream commit 39c71a5b8212f4b502d9a630c6706ac723abd422 ]

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>
Fixes: a4ffb13c8946 ("dmaengine: Add STM32 MDMA driver")
Link: https://lore.kernel.org/r/20190729020849.17971-1-baijiaju1990@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c
index daa1602eb9f55af734256408974a8935bfbbe948..356baa87a6b390b84a707c7efade0e09a213e4a8 100644 (file)
--- a/drivers/dma/stm32-mdma.c
+++ b/drivers/dma/stm32-mdma.c
@@ -1358,7 +1358,7 @@ 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;
        }