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Message-ID: <c2c3b573-0e62-4452-e657-fbef9abb9430@quicinc.com>
Date: Mon, 8 Apr 2024 09:51:43 -0700
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Subject: Re: [PATCH] drm/msm/dpu: Add callback function pointer check before
 its call
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To: Aleksandr Mishin <amishin@t-argos.ru>,
        Dmitry Baryshkov
	<dmitry.baryshkov@linaro.org>
CC: Rob Clark <robdclark@gmail.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>
References: <20240408085523.12231-1-amishin@t-argos.ru>
From: Abhinav Kumar <quic_abhinavk@quicinc.com>
In-Reply-To: <20240408085523.12231-1-amishin@t-argos.ru>
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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);
>