Re: [PATCH] drm/msm/dsi: Add missing check for alloc_ordered_workqueue

[Dmitry Baryshkov]

On 06/01/2023 04:56, Jiasheng Jiang wrote:
> Add check for the return value of alloc_ordered_workqueue as it may return
> NULL pointer and cause NULL pointer dereference.
> Moreover, change the "return ret" into "goto fail" in order to be
> consistent with the others.
>
> Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support")
> Fixes: 32d3e0feccfe ("drm/msm: dsi: Use OPP API to set clk/perf state")
> Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 13 +++++++++----
>   1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 89aadd3b3202..12239f628d5a 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -1944,19 +1944,19 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
>   
>   	ret = devm_pm_opp_set_clkname(&pdev->dev, "byte");
>   	if (ret)
> -		return ret;
> +		goto fail;

fail: is just 'return ret', so these changes are not required. Instead 
the fail label can be dropped.

>   	/* OPP table is optional */
>   	ret = devm_pm_opp_of_add_table(&pdev->dev);
>   	if (ret && ret != -ENODEV) {
>   		dev_err(&pdev->dev, "invalid OPP table in device tree\n");
> -		return ret;
> +		goto fail;
>   	}
>   
>   	msm_host->irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
>   	if (msm_host->irq < 0) {
>   		ret = msm_host->irq;
>   		dev_err(&pdev->dev, "failed to get irq: %d\n", ret);
> -		return ret;
> +		goto fail;
>   	}
>   
>   	/* do not autoenable, will be enabled later */
> @@ -1966,7 +1966,7 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
>   	if (ret < 0) {
>   		dev_err(&pdev->dev, "failed to request IRQ%u: %d\n",
>   				msm_host->irq, ret);
> -		return ret;
> +		goto fail;
>   	}
>   
>   	init_completion(&msm_host->dma_comp);
> @@ -1977,6 +1977,11 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
>   
>   	/* setup workqueue */
>   	msm_host->workqueue = alloc_ordered_workqueue("dsi_drm_work", 0);
> +	if (!msm_host->workqueue) {
> +		ret = -ENOMEM;
> +		goto fail;
> +	}
> +
>   	INIT_WORK(&msm_host->err_work, dsi_err_worker);
>   
>   	msm_dsi->id = msm_host->id;

--
With best wishes
Dmitry