[RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error

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* [RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error
@ 2021-10-27  5:56 Kishon Vijay Abraham I
  2021-10-27  5:56 ` [RESEND PATCH v2 1/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA Kishon Vijay Abraham I
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Kishon Vijay Abraham I @ 2021-10-27  5:56 UTC (permalink / raw)
  To: Peter Ujfalusi, Vinod Koul
  Cc: dmaengine, linux-kernel, Vignesh Raghavendra,
	Kishon Vijay Abraham I

NULL pointer de-reference error was observed when all the PCIe endpoint
functions (22 function in J721E) request a DMA channel. The issue was
specfically observed in BCDMA (Block copy DMA) but the issue is
applicable in PKTDMA as well.

Changes from v1:
1) Split the patch for BCDMA and PKTDMA separately
2) Fixed the return value of udma_get_rflow() to 0.
3) Removed the fixes tag as the patches does not directly apply to the
commits.

v1 => https://lore.kernel.org/r/20210209090036.30832-1-kishon@ti.com

Kishon Vijay Abraham I (2):
  dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA
  dmaengine: ti: k3-udma: Fix NULL pointer dereference error for PKTDMA

 drivers/dma/ti/k3-udma.c | 32 ++++++++++++++++++++++++++------
 1 file changed, 26 insertions(+), 6 deletions(-)

-- 
2.17.1

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [RESEND PATCH v2 1/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA
  2021-10-27  5:56 [RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error Kishon Vijay Abraham I
@ 2021-10-27  5:56 ` Kishon Vijay Abraham I
  2021-10-27  5:56 ` [RESEND PATCH v2 2/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for PKTDMA Kishon Vijay Abraham I
  2021-10-27  8:45 ` [RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error Péter Ujfalusi
  2 siblings, 0 replies; 4+ messages in thread
From: Kishon Vijay Abraham I @ 2021-10-27  5:56 UTC (permalink / raw)
  To: Peter Ujfalusi, Vinod Koul
  Cc: dmaengine, linux-kernel, Vignesh Raghavendra,
	Kishon Vijay Abraham I

bcdma_get_*() checks if bchan is already allocated by checking if it
has a NON NULL value. For the error cases, bchan will have error value
and bcdma_get_*() considers this as already allocated (PASS) since the
error values are NON NULL. This results in NULL pointer dereference
error while de-referencing bchan.

Reset the value of bchan to NULL if the allocation actually fails.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 drivers/dma/ti/k3-udma.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index a35858610780..14ae28830871 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -1348,6 +1348,7 @@ static int bcdma_get_bchan(struct udma_chan *uc)
 {
 	struct udma_dev *ud = uc->ud;
 	enum udma_tp_level tpl;
+	int ret;
 
 	if (uc->bchan) {
 		dev_dbg(ud->dev, "chan%d: already have bchan%d allocated\n",
@@ -1365,8 +1366,11 @@ static int bcdma_get_bchan(struct udma_chan *uc)
 		tpl = ud->bchan_tpl.levels - 1;
 
 	uc->bchan = __udma_reserve_bchan(ud, tpl, -1);
-	if (IS_ERR(uc->bchan))
-		return PTR_ERR(uc->bchan);
+	if (IS_ERR(uc->bchan)) {
+		ret = PTR_ERR(uc->bchan);
+		uc->bchan = NULL;
+		return ret;
+	}
 
 	uc->tchan = uc->bchan;
 
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [RESEND PATCH v2 2/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for PKTDMA
  2021-10-27  5:56 [RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error Kishon Vijay Abraham I
  2021-10-27  5:56 ` [RESEND PATCH v2 1/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA Kishon Vijay Abraham I
@ 2021-10-27  5:56 ` Kishon Vijay Abraham I
  2021-10-27  8:45 ` [RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error Péter Ujfalusi
  2 siblings, 0 replies; 4+ messages in thread
From: Kishon Vijay Abraham I @ 2021-10-27  5:56 UTC (permalink / raw)
  To: Peter Ujfalusi, Vinod Koul
  Cc: dmaengine, linux-kernel, Vignesh Raghavendra,
	Kishon Vijay Abraham I

udma_get_*() checks if rchan/tchan/rflow is already allocated by checking
if it has a NON NULL value. For the error cases, rchan/tchan/rflow will
have error value and udma_get_*() considers this as already allocated
(PASS) since the error values are NON NULL. This results in NULL pointer
dereference error while de-referencing rchan/tchan/rflow.

Reset the value of rchan/tchan/rflow to NULL if the allocation actually
fails.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 drivers/dma/ti/k3-udma.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index 14ae28830871..041d8e32d630 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -1380,6 +1380,7 @@ static int bcdma_get_bchan(struct udma_chan *uc)
 static int udma_get_tchan(struct udma_chan *uc)
 {
 	struct udma_dev *ud = uc->ud;
+	int ret;
 
 	if (uc->tchan) {
 		dev_dbg(ud->dev, "chan%d: already have tchan%d allocated\n",
@@ -1394,8 +1395,11 @@ static int udma_get_tchan(struct udma_chan *uc)
 	 */
 	uc->tchan = __udma_reserve_tchan(ud, uc->config.channel_tpl,
 					 uc->config.mapped_channel_id);
-	if (IS_ERR(uc->tchan))
-		return PTR_ERR(uc->tchan);
+	if (IS_ERR(uc->tchan)) {
+		ret = PTR_ERR(uc->tchan);
+		uc->tchan = NULL;
+		return ret;
+	}
 
 	if (ud->tflow_cnt) {
 		int tflow_id;
@@ -1425,6 +1429,7 @@ static int udma_get_tchan(struct udma_chan *uc)
 static int udma_get_rchan(struct udma_chan *uc)
 {
 	struct udma_dev *ud = uc->ud;
+	int ret;
 
 	if (uc->rchan) {
 		dev_dbg(ud->dev, "chan%d: already have rchan%d allocated\n",
@@ -1439,8 +1444,13 @@ static int udma_get_rchan(struct udma_chan *uc)
 	 */
 	uc->rchan = __udma_reserve_rchan(ud, uc->config.channel_tpl,
 					 uc->config.mapped_channel_id);
+	if (IS_ERR(uc->rchan)) {
+		ret = PTR_ERR(uc->rchan);
+		uc->rchan = NULL;
+		return ret;
+	}
 
-	return PTR_ERR_OR_ZERO(uc->rchan);
+	return 0;
 }
 
 static int udma_get_chan_pair(struct udma_chan *uc)
@@ -1494,6 +1504,7 @@ static int udma_get_chan_pair(struct udma_chan *uc)
 static int udma_get_rflow(struct udma_chan *uc, int flow_id)
 {
 	struct udma_dev *ud = uc->ud;
+	int ret;
 
 	if (!uc->rchan) {
 		dev_err(ud->dev, "chan%d: does not have rchan??\n", uc->id);
@@ -1507,8 +1518,13 @@ static int udma_get_rflow(struct udma_chan *uc, int flow_id)
 	}
 
 	uc->rflow = __udma_get_rflow(ud, flow_id);
+	if (IS_ERR(uc->rflow)) {
+		ret = PTR_ERR(uc->rflow);
+		uc->rflow = NULL;
+		return ret;
+	}
 
-	return PTR_ERR_OR_ZERO(uc->rflow);
+	return 0;
 }
 
 static void bcdma_put_bchan(struct udma_chan *uc)
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error
  2021-10-27  5:56 [RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error Kishon Vijay Abraham I
  2021-10-27  5:56 ` [RESEND PATCH v2 1/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA Kishon Vijay Abraham I
  2021-10-27  5:56 ` [RESEND PATCH v2 2/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for PKTDMA Kishon Vijay Abraham I
@ 2021-10-27  8:45 ` Péter Ujfalusi
  2 siblings, 0 replies; 4+ messages in thread
From: Péter Ujfalusi @ 2021-10-27  8:45 UTC (permalink / raw)
  To: Kishon Vijay Abraham I, Vinod Koul
  Cc: dmaengine, linux-kernel, Vignesh Raghavendra

Hi Kishon,

On 27/10/2021 08:56, Kishon Vijay Abraham I wrote:
> NULL pointer de-reference error was observed when all the PCIe endpoint
> functions (22 function in J721E) request a DMA channel. The issue was
> specfically observed in BCDMA (Block copy DMA) but the issue is
> applicable in PKTDMA as well.

Nice catch, interesting that it did not materialized before.

Can you re-word the patch subjects and commit messages accordingly?

This is not really BCDMA/PKTDMA issue but a missed uc->Xchan = NULL;
which would cause the de-reference error.

> Changes from v1:
> 1) Split the patch for BCDMA and PKTDMA separately
> 2) Fixed the return value of udma_get_rflow() to 0.
> 3) Removed the fixes tag as the patches does not directly apply to the
> commits.
> 
> v1 => https://lore.kernel.org/r/20210209090036.30832-1-kishon@ti.com
> 
> Kishon Vijay Abraham I (2):
>   dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA

dmaengine: ti: k3-udma: Set bchan to NULL if a channel request fail

>   dmaengine: ti: k3-udma: Fix NULL pointer dereference error for PKTDMA

dmaengine: ti: k3-udma: Set rchan/tchan to NULL if a channel request fail

This is also applicable for UDMA which only have rchan and tchan.

> 
>  drivers/dma/ti/k3-udma.c | 32 ++++++++++++++++++++++++++------
>  1 file changed, 26 insertions(+), 6 deletions(-)
> 

-- 
Péter

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-10-27  8:45 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2021-10-27  5:56 [RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error Kishon Vijay Abraham I
2021-10-27  5:56 ` [RESEND PATCH v2 1/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA Kishon Vijay Abraham I
2021-10-27  5:56 ` [RESEND PATCH v2 2/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for PKTDMA Kishon Vijay Abraham I
2021-10-27  8:45 ` [RESEND PATCH v2 0/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error Péter Ujfalusi

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