drm/msm/dpu: Add callback function pointer check before its call

[PATCH] drm/msm/dpu: Add callback function pointer check before its call

Posted by Aleksandr Mishin 1 year, 10 months ago

In dpu_core_irq_callback_handler() callback function pointer is compared to NULL,
but then callback function is unconditionally called by this pointer.
Fix this bug by adding conditional return.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: c929ac60b3ed ("drm/msm/dpu: allow just single IRQ callback")
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
index 946dd0135dff..03a16fbd4c99 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
@@ -223,9 +223,11 @@ static void dpu_core_irq_callback_handler(struct dpu_kms *dpu_kms, unsigned int
 
 	VERB("IRQ=[%d, %d]\n", DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
 
-	if (!irq_entry->cb)
+	if (!irq_entry->cb) {
 		DRM_ERROR("no registered cb, IRQ=[%d, %d]\n",
 			  DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
+		return;
+	}
 
 	atomic_inc(&irq_entry->count);
 
-- 
2.30.2

Re: [PATCH] drm/msm/dpu: Add callback function pointer check before its call

Posted by Abhinav Kumar 1 year, 10 months ago


On 4/8/2024 1:55 AM, Aleksandr Mishin wrote:
> In dpu_core_irq_callback_handler() callback function pointer is compared to NULL,
> but then callback function is unconditionally called by this pointer.
> Fix this bug by adding conditional return.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 

Yes , as dmitry wrote, this should be Reported-by.

But rest LGTM.

> Fixes: c929ac60b3ed ("drm/msm/dpu: allow just single IRQ callback")
> Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> index 946dd0135dff..03a16fbd4c99 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> @@ -223,9 +223,11 @@ static void dpu_core_irq_callback_handler(struct dpu_kms *dpu_kms, unsigned int
>   
>   	VERB("IRQ=[%d, %d]\n", DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
>   
> -	if (!irq_entry->cb)
> +	if (!irq_entry->cb) {
>   		DRM_ERROR("no registered cb, IRQ=[%d, %d]\n",
>   			  DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
> +		return;
> +	}
>   
>   	atomic_inc(&irq_entry->count);
>

Re: [PATCH] drm/msm/dpu: Add callback function pointer check before its call

Posted by Aleksandr Mishin 1 year, 10 months ago


On 08.04.2024 19:51, Abhinav Kumar wrote:
> 
> 
> On 4/8/2024 1:55 AM, Aleksandr Mishin wrote:
>> In dpu_core_irq_callback_handler() callback function pointer is 
>> compared to NULL,
>> but then callback function is unconditionally called by this pointer.
>> Fix this bug by adding conditional return.
>>
>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>>
> 
> Yes , as dmitry wrote, this should be Reported-by.
> 

It is an established practice for our project, you can find 700+ applied
patches with similar line:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=linuxtesting.org

> But rest LGTM.
> 
>> Fixes: c929ac60b3ed ("drm/msm/dpu: allow just single IRQ callback")
>> Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
>> ---
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c 
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
>> index 946dd0135dff..03a16fbd4c99 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
>> @@ -223,9 +223,11 @@ static void dpu_core_irq_callback_handler(struct 
>> dpu_kms *dpu_kms, unsigned int
>>       VERB("IRQ=[%d, %d]\n", DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
>> -    if (!irq_entry->cb)
>> +    if (!irq_entry->cb) {
>>           DRM_ERROR("no registered cb, IRQ=[%d, %d]\n",
>>                 DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
>> +        return;
>> +    }
>>       atomic_inc(&irq_entry->count);

-- 
Kind regards
Aleksandr

Re: [PATCH] drm/msm/dpu: Add callback function pointer check before its call

Posted by Dmitry Baryshkov 1 year, 10 months ago

On Mon, 8 Apr 2024 at 11:57, Aleksandr Mishin <amishin@t-argos.ru> wrote:
>
> In dpu_core_irq_callback_handler() callback function pointer is compared to NULL,
> but then callback function is unconditionally called by this pointer.
> Fix this bug by adding conditional return.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.

This should be converted to a proper Reported-by: trailer.

>
> Fixes: c929ac60b3ed ("drm/msm/dpu: allow just single IRQ callback")
> Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> index 946dd0135dff..03a16fbd4c99 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> @@ -223,9 +223,11 @@ static void dpu_core_irq_callback_handler(struct dpu_kms *dpu_kms, unsigned int
>
>         VERB("IRQ=[%d, %d]\n", DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
>
> -       if (!irq_entry->cb)
> +       if (!irq_entry->cb) {
>                 DRM_ERROR("no registered cb, IRQ=[%d, %d]\n",
>                           DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
> +               return;
> +       }
>
>         atomic_inc(&irq_entry->count);
>
> --
> 2.30.2
>
>


-- 
With best wishes
Dmitry

Re: [PATCH] drm/msm/dpu: Add callback function pointer check before its call

Posted by Aleksandr Mishin 1 year, 10 months ago


On 08.04.2024 12:03, Dmitry Baryshkov wrote:
> On Mon, 8 Apr 2024 at 11:57, Aleksandr Mishin <amishin@t-argos.ru> wrote:
>>
>> In dpu_core_irq_callback_handler() callback function pointer is compared to NULL,
>> but then callback function is unconditionally called by this pointer.
>> Fix this bug by adding conditional return.
>>
>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> This should be converted to a proper Reported-by: trailer.
> 

It is an established practice for our project, you can find 700+ applied
patches with similar line:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=linuxtesting.org

>>
>> Fixes: c929ac60b3ed ("drm/msm/dpu: allow just single IRQ callback")
>> Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
>> ---
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
>> index 946dd0135dff..03a16fbd4c99 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
>> @@ -223,9 +223,11 @@ static void dpu_core_irq_callback_handler(struct dpu_kms *dpu_kms, unsigned int
>>
>>          VERB("IRQ=[%d, %d]\n", DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
>>
>> -       if (!irq_entry->cb)
>> +       if (!irq_entry->cb) {
>>                  DRM_ERROR("no registered cb, IRQ=[%d, %d]\n",
>>                            DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
>> +               return;
>> +       }
>>
>>          atomic_inc(&irq_entry->count);
>>
>> --
>> 2.30.2
>>
>>
> 
> 

-- 
Kind regards
Aleksandr

Re: [PATCH] drm/msm/dpu: Add callback function pointer check before its call

Posted by Dmitry Baryshkov 1 year, 10 months ago

On Wed, 10 Apr 2024 at 14:53, Aleksandr Mishin <amishin@t-argos.ru> wrote:
> On 08.04.2024 12:03, Dmitry Baryshkov wrote:
> > On Mon, 8 Apr 2024 at 11:57, Aleksandr Mishin <amishin@t-argos.ru> wrote:
> >>
> >> In dpu_core_irq_callback_handler() callback function pointer is compared to NULL,
> >> but then callback function is unconditionally called by this pointer.
> >> Fix this bug by adding conditional return.
> >>
> >> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> >
> > This should be converted to a proper Reported-by: trailer.
> >
>
> It is an established practice for our project, you can find 700+ applied
> patches with similar line:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=linuxtesting.org

Is there any reason why your project doesn't follow established
guidelines? Compare this to other robots.

Anyway:

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

>
> >>
> >> Fixes: c929ac60b3ed ("drm/msm/dpu: allow just single IRQ callback")
> >> Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
> >> ---
> >>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c | 4 +++-
> >>   1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> >> index 946dd0135dff..03a16fbd4c99 100644
> >> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> >> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> >> @@ -223,9 +223,11 @@ static void dpu_core_irq_callback_handler(struct dpu_kms *dpu_kms, unsigned int
> >>
> >>          VERB("IRQ=[%d, %d]\n", DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
> >>
> >> -       if (!irq_entry->cb)
> >> +       if (!irq_entry->cb) {
> >>                  DRM_ERROR("no registered cb, IRQ=[%d, %d]\n",
> >>                            DPU_IRQ_REG(irq_idx), DPU_IRQ_BIT(irq_idx));
> >> +               return;
> >> +       }
> >>
> >>          atomic_inc(&irq_entry->count);
> >>
> >> --
> >> 2.30.2
> >>
> >>
> >
> >
>
> --
> Kind regards
> Aleksandr



-- 
With best wishes
Dmitry