[PATCH v2 04/23] interconnect: imx: fix registration race

Johan Hovold posted 23 patches 2 years, 6 months ago
[PATCH v2 04/23] interconnect: imx: fix registration race
Posted by Johan Hovold 2 years, 6 months ago
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: f0d8048525d7 ("interconnect: Add imx core driver")
Cc: stable@vger.kernel.org      # 5.8
Cc: Alexandre Bailon <abailon@baylibre.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/interconnect/imx/imx.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/interconnect/imx/imx.c b/drivers/interconnect/imx/imx.c
index 823d9be9771a..979ed610f704 100644
--- a/drivers/interconnect/imx/imx.c
+++ b/drivers/interconnect/imx/imx.c
@@ -295,6 +295,9 @@ int imx_icc_register(struct platform_device *pdev,
 	provider->xlate = of_icc_xlate_onecell;
 	provider->data = data;
 	provider->dev = dev->parent;
+
+	icc_provider_init(provider);
+
 	platform_set_drvdata(pdev, imx_provider);
 
 	if (settings) {
@@ -306,20 +309,18 @@ int imx_icc_register(struct platform_device *pdev,
 		}
 	}
 
-	ret = icc_provider_add(provider);
-	if (ret) {
-		dev_err(dev, "error adding interconnect provider: %d\n", ret);
+	ret = imx_icc_register_nodes(imx_provider, nodes, nodes_count, settings);
+	if (ret)
 		return ret;
-	}
 
-	ret = imx_icc_register_nodes(imx_provider, nodes, nodes_count, settings);
+	ret = icc_provider_register(provider);
 	if (ret)
-		goto provider_del;
+		goto err_unregister_nodes;
 
 	return 0;
 
-provider_del:
-	icc_provider_del(provider);
+err_unregister_nodes:
+	imx_icc_unregister_nodes(&imx_provider->provider);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(imx_icc_register);
@@ -328,9 +329,8 @@ void imx_icc_unregister(struct platform_device *pdev)
 {
 	struct imx_icc_provider *imx_provider = platform_get_drvdata(pdev);
 
+	icc_provider_deregister(&imx_provider->provider);
 	imx_icc_unregister_nodes(&imx_provider->provider);
-
-	icc_provider_del(&imx_provider->provider);
 }
 EXPORT_SYMBOL_GPL(imx_icc_unregister);
 
-- 
2.39.2
Re: [PATCH v2 04/23] interconnect: imx: fix registration race
Posted by Luca Ceresoli 2 years, 6 months ago
On Mon,  6 Mar 2023 08:56:32 +0100
Johan Hovold <johan+linaro@kernel.org> 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.
> 
> Switch to using the new API where the provider is not registered until
> after it has been fully initialised.
> 
> Fixes: f0d8048525d7 ("interconnect: Add imx core driver")
> Cc: stable@vger.kernel.org      # 5.8
> Cc: Alexandre Bailon <abailon@baylibre.com>
> Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

v2 works just as well, so my Tested-by is confirmed. Maybe it's useful
mentioning the hardware used for testing so:

[Tested on i.MX8MP using an MSC SM2-MB-EP1 Board]
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
Re: [PATCH v2 04/23] interconnect: imx: fix registration race
Posted by Johan Hovold 2 years, 6 months ago
On Tue, Mar 07, 2023 at 10:43:24AM +0100, Luca Ceresoli wrote:
> On Mon,  6 Mar 2023 08:56:32 +0100
> Johan Hovold <johan+linaro@kernel.org> 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.
> > 
> > Switch to using the new API where the provider is not registered until
> > after it has been fully initialised.
> > 
> > Fixes: f0d8048525d7 ("interconnect: Add imx core driver")
> > Cc: stable@vger.kernel.org      # 5.8
> > Cc: Alexandre Bailon <abailon@baylibre.com>
> > Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> > Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> 
> v2 works just as well, so my Tested-by is confirmed. Maybe it's useful
> mentioning the hardware used for testing so:
> 
> [Tested on i.MX8MP using an MSC SM2-MB-EP1 Board]
> Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Thanks for reconfirming. Looks like Georgi has picked these up for
6.3-rc now.

Johan