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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date: Mon, 8 Apr 2024 12:03:04 +0300
Message-ID: <CAA8EJppTM4tpsFaZKupPe=0Oc9qDp7dBqHyHGP4E5bTHKT=hSw@mail.gmail.com>
Subject: Re: [PATCH] drm/msm/dpu: Add callback function pointer check before
 its call
To: Aleksandr Mishin <amishin@t-argos.ru>
Cc: Rob Clark <robdclark@gmail.com>, Abhinav Kumar <quic_abhinavk@quicinc.com>, 
	Sean Paul <sean@poorly.run>, Marijn Suijten <marijn.suijten@somainline.org>, 
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, 
	Neil Armstrong <neil.armstrong@linaro.org>, Stephen Boyd <swboyd@chromium.org>, 
	linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, 
	freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org, 
	lvc-project@linuxtesting.org
Content-Type: text/plain; charset="UTF-8"

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