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

[Dmitry Baryshkov]

On Mon, 8 Apr 2024 at 11:57, Aleksandr Mishin <amishin@xxxxxxxxxx> 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@xxxxxxxxxx>
> ---
>  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