interconnect: exynos: fix registration race

commit c9e46ca612cfbb0cf890f7ae7389b742e90efe64 upstream.

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 trigger a NULL-pointer
deference when either a NULL pointer or not fully initialised node is
returned from exynos_generic_icc_xlate().

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

Fixes: 2f95b9d5cf0b ("interconnect: Add generic interconnect driver for Exynos SoCs")
Cc: stable@vger.kernel.org      # 5.11
Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20230306075651.2449-16-johan+linaro@kernel.org
Signed-off-by: Georgi Djakov <djakov@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 10 insertions, 10 deletions

diff --git a/drivers/interconnect/samsung/exynos.c b/drivers/interconnect/samsung/exynos.c
index e70665899482..72e42603823b 100644
--- a/drivers/interconnect/samsung/exynos.c
+++ b/drivers/interconnect/samsung/exynos.c
@@ -98,12 +98,13 @@ static int exynos_generic_icc_remove(struct platform_device *pdev)
 	struct exynos_icc_priv *priv = platform_get_drvdata(pdev);
 	struct icc_node *parent_node, *node = priv->node;
 
+	icc_provider_deregister(&priv->provider);
+
 	parent_node = exynos_icc_get_parent(priv->dev->parent->of_node);
 	if (parent_node && !IS_ERR(parent_node))
 		icc_link_destroy(node, parent_node);
 
 	icc_nodes_remove(&priv->provider);
-	icc_provider_del(&priv->provider);
 
 	return 0;
 }
@@ -132,15 +133,11 @@ static int exynos_generic_icc_probe(struct platform_device *pdev)
 	provider->inter_set = true;
 	provider->data = priv;
 
-	ret = icc_provider_add(provider);
-	if (ret < 0)
-		return ret;
+	icc_provider_init(provider);
 
 	icc_node = icc_node_create(pdev->id);
-	if (IS_ERR(icc_node)) {
-		ret = PTR_ERR(icc_node);
-		goto err_prov_del;
-	}
+	if (IS_ERR(icc_node))
+		return PTR_ERR(icc_node);
 
 	priv->node = icc_node;
 	icc_node->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
@@ -171,14 +168,17 @@ static int exynos_generic_icc_probe(struct platform_device *pdev)
 			goto err_pmqos_del;
 	}
 
+	ret = icc_provider_register(provider);
+	if (ret < 0)
+		goto err_pmqos_del;
+
 	return 0;
 
 err_pmqos_del:
 	dev_pm_qos_remove_request(&priv->qos_req);
 err_node_del:
 	icc_nodes_remove(provider);
-err_prov_del:
-	icc_provider_del(provider);
+
 	return ret;
 }