LinuxLists.cc - [PATCH 1/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA

2021-10-27 18:00:46

Subject: [PATCH 1/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA

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 <[email protected]>
---
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

2021-10-27 18:00:46

by Kishon Vijay Abraham I

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Subject: Re: [PATCH 1/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA

Hi All,

On 27/10/21 11:22 am, Kishon Vijay Abraham I wrote:
> 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 <[email protected]>

Please ignore this series. There was some stray patches left which I failed to
notice before sending. I'll resend a clean one.

Thanks,
Kishon
> ---
> 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;
>
>

2021-10-27 18:00:46

by Kishon Vijay Abraham I

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Subject: [PATCH 2/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for PKTDMA

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 <[email protected]>
---
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

2021-10-27 18:00:46

by Kishon Vijay Abraham I

[permalink] [raw]

Subject: [PATCH v2 2/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for PKTDMA

2021-10-27 18:00:49

by Kishon Vijay Abraham I

[permalink] [raw]

Subject: [PATCH v2 1/2] dmaengine: ti: k3-udma: Fix NULL pointer dereference error for BCDMA

2021-10-27 18:02:12

by Kishon Vijay Abraham I

[permalink] [raw]

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

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/[email protected]

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