[PATCH 15/23] interconnect: exynos: fix registration race

Johan Hovold
2023-02-01T10:17:03Z

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>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
drivers/interconnect/samsung/exynos.c | 20 ++++++++++----------
1 file 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;
}

--
2.39.1