2024-04-08 08:59:45

by Aleksandr Mishin

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

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 <[email protected]>
---
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

2024-04-08 09:03:34

by Dmitry Baryshkov

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

On Mon, 8 Apr 2024 at 11:57, Aleksandr Mishin <[email protected]> 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 <[email protected]>
> ---
> 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

2024-04-08 16:52:35

by Abhinav Kumar

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

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 <[email protected]>
> ---
> 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);
>

2024-04-10 11:54:29

by Aleksandr Mishin

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

On 08.04.2024 12:03, Dmitry Baryshkov wrote:
> On Mon, 8 Apr 2024 at 11:57, Aleksandr Mishin <[email protected]> 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 <[email protected]>
>> ---
>> 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

2024-04-10 11:54:30

by Aleksandr Mishin

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

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 <[email protected]>
>> ---
>>   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

2024-04-10 14:10:34

by Dmitry Baryshkov

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

On Wed, 10 Apr 2024 at 14:53, Aleksandr Mishin <[email protected]> wrote:
> On 08.04.2024 12:03, Dmitry Baryshkov wrote:
> > On Mon, 8 Apr 2024 at 11:57, Aleksandr Mishin <[email protected]> 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 <[email protected]>

>
> >>
> >> Fixes: c929ac60b3ed ("drm/msm/dpu: allow just single IRQ callback")
> >> Signed-off-by: Aleksandr Mishin <[email protected]>
> >> ---
> >> 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