From:   Johan Hovold <johan+linaro@kernel.org>
To:     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>,
        "Konrad Dybcio" <konrad.dybcio@linaro.org>,
        "Sylwester Nawrocki" <s.nawrocki@samsung.com>,
        =?UTF-8?q?Artur=20=C5=9Awigo=C5=84?= <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,
        Johan Hovold <johan+linaro@kernel.org>, stable@vger.kernel.org,
        Dmitry Osipenko <digetx@gmail.com>
Subject: [PATCH v2 17/23] memory: tegra: fix interconnect registration race
Date:   Mon,  6 Mar 2023 08:56:45 +0100
Message-Id: <20230306075651.2449-18-johan+linaro@kernel.org>
In-Reply-To: <20230306075651.2449-1-johan+linaro@kernel.org>
References: <20230306075651.2449-1-johan+linaro@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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.

Switch to using the new API where the provider is not registered until
after it has been fully initialised.

Fixes: 06f079816d4c ("memory: tegra-mc: Add interconnect framework")
Cc: stable@vger.kernel.org      # 5.11
Cc: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/memory/tegra/mc.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index 592907546ee6..5cd28619ea9f 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -794,16 +794,12 @@ static int tegra_mc_interconnect_setup(struct tegra_mc *mc)
 	mc->provider.aggregate = mc->soc->icc_ops->aggregate;
 	mc->provider.xlate_extended = mc->soc->icc_ops->xlate_extended;
 
-	err = icc_provider_add(&mc->provider);
-	if (err)
-		return err;
+	icc_provider_init(&mc->provider);
 
 	/* create Memory Controller node */
 	node = icc_node_create(TEGRA_ICC_MC);
-	if (IS_ERR(node)) {
-		err = PTR_ERR(node);
-		goto del_provider;
-	}
+	if (IS_ERR(node))
+		return PTR_ERR(node);
 
 	node->name = "Memory Controller";
 	icc_node_add(node, &mc->provider);
@@ -830,12 +826,14 @@ static int tegra_mc_interconnect_setup(struct tegra_mc *mc)
 			goto remove_nodes;
 	}
 
+	err = icc_provider_register(&mc->provider);
+	if (err)
+		goto remove_nodes;
+
 	return 0;
 
 remove_nodes:
 	icc_nodes_remove(&mc->provider);
-del_provider:
-	icc_provider_del(&mc->provider);
 
 	return err;
 }
-- 
2.39.2