2022-12-06 08:26:20

by Jiasheng Jiang

Subject: [PATCH] drm/msm/dpu: Add check for cstate

As kzalloc may fail and return NULL pointer,
it should be better to check cstate
in order to avoid the NULL pointer dereference
in __drm_atomic_helper_crtc_reset.

Fixes: 1cff7440a86e ("drm/msm: Convert to using __drm_atomic_helper_crtc_reset() for reset.")
Signed-off-by: Jiasheng Jiang <[email protected]>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index 13ce321283ff..22c2787b7b38 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -968,7 +968,10 @@ static void dpu_crtc_reset(struct drm_crtc *crtc)
if (crtc->state)
dpu_crtc_destroy_state(crtc, crtc->state);

- __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
+ if (cstate)
+ __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
+ else
+ __drm_atomic_helper_crtc_reset(crtc, NULL);
}

/**
--
2.25.1

2022-12-06 17:37:22

by Abhinav Kumar

Subject: Re: [PATCH] drm/msm/dpu: Add check for cstate

On 12/6/2022 12:05 AM, Jiasheng Jiang wrote:
> As kzalloc may fail and return NULL pointer,
> it should be better to check cstate
> in order to avoid the NULL pointer dereference
> in __drm_atomic_helper_crtc_reset.

You have wrapped around your lines too short. Please try to utilize the
full word limit for each line.

With that fixed,

Reviewed-by: Abhinav Kumar <[email protected]>

>
> Fixes: 1cff7440a86e ("drm/msm: Convert to using __drm_atomic_helper_crtc_reset() for reset.")
> Signed-off-by: Jiasheng Jiang <[email protected]>
> ---
> drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index 13ce321283ff..22c2787b7b38 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -968,7 +968,10 @@ static void dpu_crtc_reset(struct drm_crtc *crtc)
> if (crtc->state)
> dpu_crtc_destroy_state(crtc, crtc->state);
>
> - __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
> + if (cstate)
> + __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
> + else
> + __drm_atomic_helper_crtc_reset(crtc, NULL);
> }
>
> /**

2023-01-08 22:18:21

by Dmitry Baryshkov

Subject: Re: [PATCH] drm/msm/dpu: Add check for cstate

On 06/12/2022 10:05, Jiasheng Jiang wrote:
> As kzalloc may fail and return NULL pointer,
> it should be better to check cstate
> in order to avoid the NULL pointer dereference
> in __drm_atomic_helper_crtc_reset.
>
> Fixes: 1cff7440a86e ("drm/msm: Convert to using __drm_atomic_helper_crtc_reset() for reset.")
> Signed-off-by: Jiasheng Jiang <[email protected]>
> ---
> drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index 13ce321283ff..22c2787b7b38 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -968,7 +968,10 @@ static void dpu_crtc_reset(struct drm_crtc *crtc)
> if (crtc->state)
> dpu_crtc_destroy_state(crtc, crtc->state);
>
> - __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
> + if (cstate)
> + __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
> + else
> + __drm_atomic_helper_crtc_reset(crtc, NULL);

NAK.

The proper fix is to add the if() but to skip the else clause. We should
not reset the crtc's state if memory allocation failed.

> }
>
> /**

--
With best wishes
Dmitry

2023-01-08 22:42:42

by Dmitry Baryshkov

Subject: Re: [PATCH] drm/msm/dpu: Add check for cstate

On 08/01/2023 23:56, Dmitry Baryshkov wrote:
> On 06/12/2022 10:05, Jiasheng Jiang wrote:
>> As kzalloc may fail and return NULL pointer,
>> it should be better to check cstate
>> in order to avoid the NULL pointer dereference
>> in __drm_atomic_helper_crtc_reset.
>>
>> Fixes: 1cff7440a86e ("drm/msm: Convert to using
>> __drm_atomic_helper_crtc_reset() for reset.")
>> Signed-off-by: Jiasheng Jiang <[email protected]>
>> ---
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 5 ++++-
>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> index 13ce321283ff..22c2787b7b38 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> @@ -968,7 +968,10 @@ static void dpu_crtc_reset(struct drm_crtc *crtc)
>>       if (crtc->state)
>>           dpu_crtc_destroy_state(crtc, crtc->state);
>> -    __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
>> +    if (cstate)
>> +        __drm_atomic_helper_crtc_reset(crtc, &cstate->base);
>> +    else
>> +        __drm_atomic_helper_crtc_reset(crtc, NULL);
>
> NAK.
>
> The proper fix is to add the if() but to skip the else clause. We should
> not reset the crtc's state if memory allocation failed.

On the other hand... Some of the drivers do exactly this ops.

With the message fixed:

Reviewed-by: Dmitry Baryshkov <[email protected]>

--
With best wishes
Dmitry

2023-01-26 19:01:31

by Dmitry Baryshkov

Subject: Re: [PATCH] drm/msm/dpu: Add check for cstate

On Tue, 06 Dec 2022 16:05:17 +0800, Jiasheng Jiang wrote:
> As kzalloc may fail and return NULL pointer,
> it should be better to check cstate
> in order to avoid the NULL pointer dereference
> in __drm_atomic_helper_crtc_reset.
>
>

Applied, thanks!

[1/1] drm/msm/dpu: Add check for cstate
https://gitlab.freedesktop.org/lumag/msm/-/commit/c96988b7d993

Best regards,
--
Dmitry Baryshkov <[email protected]>