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[next] dmaengine: ti: omap-dma: don't allow a null od->plat pointer to be dereferenced

Message ID 20200106122325.39121-1-colin.king@canonical.com (mailing list archive)
State Changes Requested
Headers show
Series [next] dmaengine: ti: omap-dma: don't allow a null od->plat pointer to be dereferenced | expand

Commit Message

Colin King Jan. 6, 2020, 12:23 p.m. UTC
From: Colin Ian King <colin.king@canonical.com>

Currently when the call to dev_get_platdata returns null the driver issues
a warning and then later dereferences the null pointer.  Avoid this issue
by returning -EPROBE_DEFER errror rather when the platform data is null.

Addresses-Coverity: ("Dereference after null check")
Fixes: 211010aeb097 ("dmaengine: ti: omap-dma: Pass sdma auxdata to driver and use it")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/dma/ti/omap-dma.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Peter Ujfalusi Jan. 7, 2020, 11:59 a.m. UTC | #1
Colin,

On 06/01/2020 14.23, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently when the call to dev_get_platdata returns null the driver issues
> a warning and then later dereferences the null pointer.  Avoid this issue
> by returning -EPROBE_DEFER errror rather when the platform data is null.

Thank you for noticing it!

Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>

> Addresses-Coverity: ("Dereference after null check")
> Fixes: 211010aeb097 ("dmaengine: ti: omap-dma: Pass sdma auxdata to driver and use it")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/dma/ti/omap-dma.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
> index fc8f7b2fc7b3..335c3fa7a3b1 100644
> --- a/drivers/dma/ti/omap-dma.c
> +++ b/drivers/dma/ti/omap-dma.c
> @@ -1658,8 +1658,10 @@ static int omap_dma_probe(struct platform_device *pdev)
>  	if (conf) {
>  		od->cfg = conf;
>  		od->plat = dev_get_platdata(&pdev->dev);
> -		if (!od->plat)
> +		if (!od->plat) {
>  			dev_warn(&pdev->dev, "no sdma auxdata needed?\n");
> +			return -EPROBE_DEFER;
> +		}
>  	} else {
>  		od->cfg = &default_cfg;
>  
> 

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Peter Ujfalusi Jan. 8, 2020, 7:20 a.m. UTC | #2
Colin, Tony,

On 07/01/2020 13.59, Peter Ujfalusi wrote:
> Colin,
> 
> On 06/01/2020 14.23, Colin King wrote:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> Currently when the call to dev_get_platdata returns null the driver issues
>> a warning and then later dereferences the null pointer.  Avoid this issue
>> by returning -EPROBE_DEFER errror rather when the platform data is null.
> 
> Thank you for noticing it!
> 
> Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> 
>> Addresses-Coverity: ("Dereference after null check")
>> Fixes: 211010aeb097 ("dmaengine: ti: omap-dma: Pass sdma auxdata to driver and use it")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
>> ---
>>  drivers/dma/ti/omap-dma.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
>> index fc8f7b2fc7b3..335c3fa7a3b1 100644
>> --- a/drivers/dma/ti/omap-dma.c
>> +++ b/drivers/dma/ti/omap-dma.c
>> @@ -1658,8 +1658,10 @@ static int omap_dma_probe(struct platform_device *pdev)
>>  	if (conf) {
>>  		od->cfg = conf;
>>  		od->plat = dev_get_platdata(&pdev->dev);
>> -		if (!od->plat)
>> +		if (!od->plat) {
>>  			dev_warn(&pdev->dev, "no sdma auxdata needed?\n");
>> +			return -EPROBE_DEFER;

I think we should make the print as dev_err("&pdev->dev,
"omap_system_dma_plat_info is missing") and return with -ENODEV. The
omap_system_dma_plat_info is _needed_ and if we have booted with device
tree it is not going to appear later.

Tony, what do you think?

>> +		}
>>  	} else {
>>  		od->cfg = &default_cfg;
>>  
>>

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Tony Lindgren Jan. 8, 2020, 10:05 p.m. UTC | #3
* Peter Ujfalusi <peter.ujfalusi@ti.com> [200108 07:20]:
> Colin, Tony,
> 
> On 07/01/2020 13.59, Peter Ujfalusi wrote:
> > Colin,
> > 
> > On 06/01/2020 14.23, Colin King wrote:
> >> From: Colin Ian King <colin.king@canonical.com>
> >>
> >> Currently when the call to dev_get_platdata returns null the driver issues
> >> a warning and then later dereferences the null pointer.  Avoid this issue
> >> by returning -EPROBE_DEFER errror rather when the platform data is null.
> > 
> > Thank you for noticing it!
> > 
> > Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> > 
> >> Addresses-Coverity: ("Dereference after null check")
> >> Fixes: 211010aeb097 ("dmaengine: ti: omap-dma: Pass sdma auxdata to driver and use it")
> >> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> >> ---
> >>  drivers/dma/ti/omap-dma.c | 4 +++-
> >>  1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
> >> index fc8f7b2fc7b3..335c3fa7a3b1 100644
> >> --- a/drivers/dma/ti/omap-dma.c
> >> +++ b/drivers/dma/ti/omap-dma.c
> >> @@ -1658,8 +1658,10 @@ static int omap_dma_probe(struct platform_device *pdev)
> >>  	if (conf) {
> >>  		od->cfg = conf;
> >>  		od->plat = dev_get_platdata(&pdev->dev);
> >> -		if (!od->plat)
> >> +		if (!od->plat) {
> >>  			dev_warn(&pdev->dev, "no sdma auxdata needed?\n");
> >> +			return -EPROBE_DEFER;
> 
> I think we should make the print as dev_err("&pdev->dev,
> "omap_system_dma_plat_info is missing") and return with -ENODEV. The
> omap_system_dma_plat_info is _needed_ and if we have booted with device
> tree it is not going to appear later.
> 
> Tony, what do you think?

Yes makes sense, the auxdata is needed for the quirks for now.
Eventually the quirks can be set directly in the dmaengine driver
based on compatible and soc_device_match().

Regards,

Tony
diff mbox series

Patch

diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
index fc8f7b2fc7b3..335c3fa7a3b1 100644
--- a/drivers/dma/ti/omap-dma.c
+++ b/drivers/dma/ti/omap-dma.c
@@ -1658,8 +1658,10 @@  static int omap_dma_probe(struct platform_device *pdev)
 	if (conf) {
 		od->cfg = conf;
 		od->plat = dev_get_platdata(&pdev->dev);
-		if (!od->plat)
+		if (!od->plat) {
 			dev_warn(&pdev->dev, "no sdma auxdata needed?\n");
+			return -EPROBE_DEFER;
+		}
 	} else {
 		od->cfg = &default_cfg;