2020-03-23 09:47:32

by Kunihiko Hayashi

Subject: [PATCH] PCI: endpoint: functions/pci-epf-test: Avoid DMA release when DMA is unsupported

When unbinding pci_epf_test, pci_epf_test_clean_dma_chan() is called in
pci_epf_test_unbind() even though epf_test->dma_supported is false.
As a result, dma_release_channel() will occur null pointer access because
dma_chan isn't set.

This avoids calling dma_release_channel() if epf_test->dma_supported
is false.

Fixes: a1d105d4ab8e ("PCI: endpoint: functions/pci-epf-test: Add DMA support to transfer data")
Signed-off-by: Kunihiko Hayashi <[email protected]>
---
drivers/pci/endpoint/functions/pci-epf-test.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 3b4cf7e..8b4f136 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -609,7 +609,8 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
int bar;

cancel_delayed_work(&epf_test->cmd_handler);
- pci_epf_test_clean_dma_chan(epf_test);
+ if (epf_test->dma_supported)
+ pci_epf_test_clean_dma_chan(epf_test);
pci_epc_stop(epc);
for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
epf_bar = &epf->bar[bar];
--
2.7.4

2020-04-22 05:14:22

by Kunihiko Hayashi

Subject: Re: [PATCH] PCI: endpoint: functions/pci-epf-test: Avoid DMA release when DMA is unsupported

On 2020/03/23 18:45, Kunihiko Hayashi wrote:
> When unbinding pci_epf_test, pci_epf_test_clean_dma_chan() is called in
> pci_epf_test_unbind() even though epf_test->dma_supported is false.
> As a result, dma_release_channel() will occur null pointer access because
> dma_chan isn't set.
>
> This avoids calling dma_release_channel() if epf_test->dma_supported
> is false.
>
> Fixes: a1d105d4ab8e ("PCI: endpoint: functions/pci-epf-test: Add DMA support to transfer data")
> Signed-off-by: Kunihiko Hayashi <[email protected]>
> ---
> drivers/pci/endpoint/functions/pci-epf-test.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 3b4cf7e..8b4f136 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -609,7 +609,8 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
> int bar;
>
> cancel_delayed_work(&epf_test->cmd_handler);
> - pci_epf_test_clean_dma_chan(epf_test);
> + if (epf_test->dma_supported)
> + pci_epf_test_clean_dma_chan(epf_test);
> pci_epc_stop(epc);
> for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
> epf_bar = &epf->bar[bar];
>

Gentle ping.
Are there any comments about that?

Thank you,

---
Best Regards
Kunihiko Hayashi

2020-04-22 05:49:17

by Kishon Vijay Abraham I

Subject: Re: [PATCH] PCI: endpoint: functions/pci-epf-test: Avoid DMA release when DMA is unsupported

Hi Kunihiko,

On 3/23/2020 3:15 PM, Kunihiko Hayashi wrote:
> When unbinding pci_epf_test, pci_epf_test_clean_dma_chan() is called in
> pci_epf_test_unbind() even though epf_test->dma_supported is false.
> As a result, dma_release_channel() will occur null pointer access because
> dma_chan isn't set.
>
> This avoids calling dma_release_channel() if epf_test->dma_supported
> is false.
>
> Fixes: a1d105d4ab8e ("PCI: endpoint: functions/pci-epf-test: Add DMA support to transfer data")
> Signed-off-by: Kunihiko Hayashi <[email protected]>
> ---
> drivers/pci/endpoint/functions/pci-epf-test.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 3b4cf7e..8b4f136 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -609,7 +609,8 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
> int bar;
>
> cancel_delayed_work(&epf_test->cmd_handler);
> - pci_epf_test_clean_dma_chan(epf_test);
> + if (epf_test->dma_supported)
> + pci_epf_test_clean_dma_chan(epf_test);

Can you add this check inside the pci_epf_test_clean_dma_chan()?

Thanks
Kishon

2020-04-22 06:00:54

by Kunihiko Hayashi

Subject: Re: [PATCH] PCI: endpoint: functions/pci-epf-test: Avoid DMA release when DMA is unsupported

Hi Kishon,

On 2020/04/22 14:45, Kishon Vijay Abraham I wrote:
> Hi Kunihiko,
>
> On 3/23/2020 3:15 PM, Kunihiko Hayashi wrote:
>> When unbinding pci_epf_test, pci_epf_test_clean_dma_chan() is called in
>> pci_epf_test_unbind() even though epf_test->dma_supported is false.
>> As a result, dma_release_channel() will occur null pointer access because
>> dma_chan isn't set.
>>
>> This avoids calling dma_release_channel() if epf_test->dma_supported
>> is false.
>>
>> Fixes: a1d105d4ab8e ("PCI: endpoint: functions/pci-epf-test: Add DMA support to transfer data")
>> Signed-off-by: Kunihiko Hayashi <[email protected]>
>> ---
>> drivers/pci/endpoint/functions/pci-epf-test.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>> index 3b4cf7e..8b4f136 100644
>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>> @@ -609,7 +609,8 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
>> int bar;
>>
>> cancel_delayed_work(&epf_test->cmd_handler);
>> - pci_epf_test_clean_dma_chan(epf_test);
>> + if (epf_test->dma_supported)
>> + pci_epf_test_clean_dma_chan(epf_test);
>
> Can you add this check inside the pci_epf_test_clean_dma_chan()?
Okay, I'll move this check to the pci_epf_test_clean_dma_chan().

Thank you,

---
Best Regards
Kunihiko Hayashi