Message-ID: <90d2631d-c9e9-1c9b-c7de-6ec84d60096b@linaro.org>
Date:   Fri, 3 Feb 2023 03:51:44 +0100
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Subject: Re: [PATCH 05/23] interconnect: qcom: osm-l3: fix registration race
Content-Language: en-US
To:     Johan Hovold <johan+linaro@kernel.org>,
        Georgi Djakov <djakov@kernel.org>
Cc:     Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Sylwester Nawrocki <s.nawrocki@samsung.com>,
        =?UTF-8?B?QXJ0dXIgxZp3aWdvxYQ=?= <a.swigon@samsung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-arm-msm@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
        linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
References: <20230201101559.15529-1-johan+linaro@kernel.org>
 <20230201101559.15529-6-johan+linaro@kernel.org>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <20230201101559.15529-6-johan+linaro@kernel.org>
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Precedence: bulk


On 1.02.2023 11:15, Johan Hovold wrote:
> The current interconnect provider registration interface is inherently
> racy as nodes are not added until the after adding the provider. This
> can specifically cause racing DT lookups to fail:
> 
> 	of_icc_xlate_onecell: invalid index 0
> 	cpu cpu0: error -EINVAL: error finding src node
> 	cpu cpu0: dev_pm_opp_of_find_icc_paths: Unable to get path0: -22
> 	qcom-cpufreq-hw: probe of 18591000.cpufreq failed with error -22
> 
> Switch to using the new API where the provider is not registered until
> after it has been fully initialised.
> 
> Fixes: 5bc9900addaf ("interconnect: qcom: Add OSM L3 interconnect provider support")
> Cc: stable@vger.kernel.org      # 5.7
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad
>  drivers/interconnect/qcom/osm-l3.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/interconnect/qcom/osm-l3.c b/drivers/interconnect/qcom/osm-l3.c
> index 5fa171087425..3a1cbfe3e481 100644
> --- a/drivers/interconnect/qcom/osm-l3.c
> +++ b/drivers/interconnect/qcom/osm-l3.c
> @@ -158,8 +158,8 @@ static int qcom_osm_l3_remove(struct platform_device *pdev)
>  {
>  	struct qcom_osm_l3_icc_provider *qp = platform_get_drvdata(pdev);
>  
> +	icc_provider_deregister(&qp->provider);
>  	icc_nodes_remove(&qp->provider);
> -	icc_provider_del(&qp->provider);
>  
>  	return 0;
>  }
> @@ -245,14 +245,9 @@ static int qcom_osm_l3_probe(struct platform_device *pdev)
>  	provider->set = qcom_osm_l3_set;
>  	provider->aggregate = icc_std_aggregate;
>  	provider->xlate = of_icc_xlate_onecell;
> -	INIT_LIST_HEAD(&provider->nodes);
>  	provider->data = data;
>  
> -	ret = icc_provider_add(provider);
> -	if (ret) {
> -		dev_err(&pdev->dev, "error adding interconnect provider\n");
> -		return ret;
> -	}
> +	icc_provider_init(provider);
>  
>  	for (i = 0; i < num_nodes; i++) {
>  		size_t j;
> @@ -275,12 +270,15 @@ static int qcom_osm_l3_probe(struct platform_device *pdev)
>  	}
>  	data->num_nodes = num_nodes;
>  
> +	ret = icc_provider_register(provider);
> +	if (ret)
> +		goto err;
> +
>  	platform_set_drvdata(pdev, qp);
>  
>  	return 0;
>  err:
>  	icc_nodes_remove(provider);
> -	icc_provider_del(provider);
>  
>  	return ret;
>  }