linux-kernel - Re: [PATCH v2] drm/msm/disp/dpu1: avoid clearing hw interrupts if hw

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Date:   Mon, 2 May 2022 20:12:04 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Vinod Polimera <quic_vpolimer@...cinc.com>,
        dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, robdclark@...il.com,
        dianders@...omium.org, swboyd@...omium.org,
        quic_kalyant@...cinc.com, quic_abhinavk@...cinc.com
Subject: Re: [PATCH v2] drm/msm/disp/dpu1: avoid clearing hw interrupts if
 hw_intr is null during drm uninit

On 02/05/2022 19:44, Vinod Polimera wrote:
> If edp modeset init is failed due to panel being not ready and
> probe defers during drm bind, avoid clearing irqs and derefernce
> hw_intr when hw_intr is null.
> 
> BUG: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> 
> Call trace:
>   dpu_core_irq_uninstall+0x50/0xb0
>   dpu_irq_uninstall+0x18/0x24
>   msm_drm_uninit+0xd8/0x16c
>   msm_drm_bind+0x580/0x5fc
>   try_to_bring_up_master+0x168/0x1c0
>   __component_add+0xb4/0x178
>   component_add+0x1c/0x28
>   dp_display_probe+0x38c/0x400
>   platform_probe+0xb0/0xd0
>   really_probe+0xcc/0x2c8
>   __driver_probe_device+0xbc/0xe8
>   driver_probe_device+0x48/0xf0
>   __device_attach_driver+0xa0/0xc8
>   bus_for_each_drv+0x8c/0xd8
>   __device_attach+0xc4/0x150
>   device_initial_probe+0x1c/0x28
> 
> Changes in V2:
> - Update commit message and coreect fixes tag.
> 
> Fixes: f25f656608e3 ("drm/msm/dpu: merge struct dpu_irq into struct dpu_hw_intr")
> Signed-off-by: Vinod Polimera <quic_vpolimer@...cinc.com>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>

> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> 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 c515b7c..ab28577 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c
> @@ -599,6 +599,9 @@ void dpu_core_irq_uninstall(struct dpu_kms *dpu_kms)
>   {
>   	int i;
>   
> +	if (!dpu_kms->hw_intr)
> +		return;
> +
>   	pm_runtime_get_sync(&dpu_kms->pdev->dev);
>   	for (i = 0; i < dpu_kms->hw_intr->total_irqs; i++)
>   		if (!list_empty(&dpu_kms->hw_intr->irq_cb_tbl[i]))


-- 
With best wishes
Dmitry