[PATCH V2 0/3] do exception handling appropriately in at_dma_xlate()

[PATCH V2 0/3] do exception handling appropriately in at_dma_xlate()

[Yu Kuai]

changes from V1:
-separate different changes to different patches, as suggested by Vinod.
Yu Kuai (3):
  dmaengine: at_hdmac: check return value of of_find_device_by_node() in
    at_dma_xlate()
  dmaengine: at_hdmac: add missing put_device() call in at_dma_xlate()
  dmaengine: at_hdmac: add missing kfree() call in at_dma_xlate()

 drivers/dma/at_hdmac.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

-- 
2.25.4

[PATCH 1/3] dmaengine: at_hdmac: check return value of of_find_device_by_node() in at_dma_xlate()

[Yu Kuai]

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>
---
 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 45bbcd6146fd..1c941f839c42 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1650,6 +1650,8 @@ 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);
-- 
2.25.4

[PATCH 2/3] dmaengine: at_hdmac: add missing put_device() call in at_dma_xlate()

[Yu Kuai]

If of_find_device_by_node() succeed, at_dma_xlate() doesn't have a
corresponding put_device(). Thus add put_device() to fix the exception
handling for this function implementation.

Fixes: bbe89c8e3d59 ("at_hdmac: move to generic DMA binding")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 drivers/dma/at_hdmac.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 1c941f839c42..bf874367097c 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1657,8 +1657,10 @@ static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
 	dma_cap_set(DMA_SLAVE, mask);
 
 	atslave = kmalloc(sizeof(*atslave), GFP_KERNEL);
-	if (!atslave)
+	if (!atslave) {
+		put_device(&dmac_pdev->dev);
 		return NULL;
+	}
 
 	atslave->cfg = ATC_DST_H2SEL_HW | ATC_SRC_H2SEL_HW;
 	/*
@@ -1687,8 +1689,10 @@ static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
 	atslave->dma_dev = &dmac_pdev->dev;
 
 	chan = dma_request_channel(mask, at_dma_filter, atslave);
-	if (!chan)
+	if (!chan) {
+		put_device(&dmac_pdev->dev);
 		return NULL;
+	}
 
 	atchan = to_at_dma_chan(chan);
 	atchan->per_if = dma_spec->args[0] & 0xff;
-- 
2.25.4

[PATCH 3/3] dmaengine: at_hdmac: add missing kfree() call in at_dma_xlate()

[Yu Kuai]

If memory allocation for 'atslave' succeed, at_dma_xlate() doesn't have a
corresponding kfree() in exception handling. Thus add kfree() for this
function implementation.

Fixes: bbe89c8e3d59 ("at_hdmac: move to generic DMA binding")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 drivers/dma/at_hdmac.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index bf874367097c..a2cf25c6e3b3 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -1691,6 +1691,7 @@ static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
 	chan = dma_request_channel(mask, at_dma_filter, atslave);
 	if (!chan) {
 		put_device(&dmac_pdev->dev);
+		kfree(atslave);
 		return NULL;
 	}
 
-- 
2.25.4

Re: [PATCH V2 0/3] do exception handling appropriately in at_dma_xlate()

[Vinod Koul]

On 17-08-20, 19:57, Yu Kuai wrote:
> changes from V1:
> -separate different changes to different patches, as suggested by Vinod.

Please write proper cover letter explaining the patch series and also
the changes from v1..

I have applied the patches.

Thanks

> Yu Kuai (3):
>   dmaengine: at_hdmac: check return value of of_find_device_by_node() in
>     at_dma_xlate()
>   dmaengine: at_hdmac: add missing put_device() call in at_dma_xlate()
>   dmaengine: at_hdmac: add missing kfree() call in at_dma_xlate()
> 
>  drivers/dma/at_hdmac.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> -- 
> 2.25.4

-- 
~Vinod