Re: [PATCH v2] drm/msm/dsi: Add missing check for alloc_ordered_workqueue

[Dhruva Gole <d-gole@ti.com>]

On 09/01/23 08:20, 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 "goto fail" into "return ret" and drop the "fail"
> label since they are the same.
> 
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
> ---

Reviewed-by: Dhruva Gole <d-gole@ti.com>

> Changelog:
> 
> v1 -> v2:
> 
> 1. Change the "goto fail" into "return ret" and drop the "fail" label.
> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 24 +++++++++++++-----------
>   1 file changed, 13 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 89aadd3b3202..819f5be5fd77 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -1884,7 +1884,7 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
>   	msm_host = devm_kzalloc(&pdev->dev, sizeof(*msm_host), GFP_KERNEL);
>   	if (!msm_host) {
>   		ret = -ENOMEM;
> -		goto fail;
> +		return ret;
>   	}
>   
>   	msm_host->pdev = pdev;
> @@ -1893,14 +1893,14 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
>   	ret = dsi_host_parse_dt(msm_host);
>   	if (ret) {
>   		pr_err("%s: failed to parse dt\n", __func__);
> -		goto fail;
> +		return ret;
>   	}
>   
>   	msm_host->ctrl_base = msm_ioremap_size(pdev, "dsi_ctrl", &msm_host->ctrl_size);
>   	if (IS_ERR(msm_host->ctrl_base)) {
>   		pr_err("%s: unable to map Dsi ctrl base\n", __func__);
>   		ret = PTR_ERR(msm_host->ctrl_base);
> -		goto fail;
> +		return ret;
>   	}
>   
>   	pm_runtime_enable(&pdev->dev);
> @@ -1909,7 +1909,7 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
>   	if (!msm_host->cfg_hnd) {
>   		ret = -EINVAL;
>   		pr_err("%s: get config failed\n", __func__);
> -		goto fail;
> +		return ret;
>   	}
>   	cfg = msm_host->cfg_hnd->cfg;
>   
> @@ -1917,7 +1917,7 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
>   	if (msm_host->id < 0) {
>   		ret = msm_host->id;
>   		pr_err("%s: unable to identify DSI host index\n", __func__);
> -		goto fail;
> +		return ret;
>   	}
>   
>   	/* fixup base address by io offset */
> @@ -1927,19 +1927,19 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi)
>   					    cfg->regulator_data,
>   					    &msm_host->supplies);
>   	if (ret)
> -		goto fail;
> +		return ret;
>   
>   	ret = dsi_clk_init(msm_host);
>   	if (ret) {
>   		pr_err("%s: unable to initialize dsi clks\n", __func__);
> -		goto fail;
> +		return ret;
>   	}
>   
>   	msm_host->rx_buf = devm_kzalloc(&pdev->dev, SZ_4K, GFP_KERNEL);
>   	if (!msm_host->rx_buf) {
>   		ret = -ENOMEM;
>   		pr_err("%s: alloc rx temp buf failed\n", __func__);
> -		goto fail;
> +		return ret;
>   	}
>   
>   	ret = devm_pm_opp_set_clkname(&pdev->dev, "byte");
> @@ -1977,15 +1977,17 @@ 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;
> +		return ret;

Why not simply return -ENOMEM;
instead?

> +	}
> +
>   	INIT_WORK(&msm_host->err_work, dsi_err_worker);
>   
>   	msm_dsi->id = msm_host->id;
>   
>   	DBG("Dsi Host %d initialized", msm_host->id);
>   	return 0;
> -
> -fail:
> -	return ret;
>   }
>   
>   void msm_dsi_host_destroy(struct mipi_dsi_host *host)

-- 
Thanks and Regards,
Dhruva Gole