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FAILED: patch "[PATCH] thermal/drivers/broadcom: Fix race between removal and clock" failed to apply to 6.6-stable tree

PATCH [email protected] 1 participant 1 message Jul 29, 2024

Subsystems (4)
Stable branch Broadcom BCM2711/BCM2835 Arm architecture Thermal Broadcom BCM281XX/BCM11XXX/BCM216XX Arm architecture
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The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x e90c369cc2ffcf7145a46448de101f715a1f5584
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024072901-rare-engaging-abb3@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

e90c369cc2ff ("thermal/drivers/broadcom: Fix race between removal and clock disable") f29ecd3748a2 ("thermal: bcm2835: Convert to platform remove callback returning void")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e90c369cc2ffcf7145a46448de101f715a1f5584 Mon Sep 17 00:00:00 2001
From: Krzysztof Kozlowski <[email protected]>
Date: Tue, 9 Jul 2024 14:59:31 +0200
Subject: [PATCH] thermal/drivers/broadcom: Fix race between removal and clock
disable

During the probe, driver enables clocks necessary to access registers (in get_temp()) and then registers thermal zone with managed-resources (devm) interface. Removal of device is not done in reversed order, because:
1. Clock will be disabled in driver remove() callback - thermal zone is still registered and accessible to users,
2. devm interface will unregister thermal zone.

This leaves short window between (1) and (2) for accessing the get_temp() callback with disabled clock.

Fix this by enabling clock also via devm-interface, so entire cleanup path will be in proper, reversed order.

Fixes 8454c8c09c77 ("thermal/drivers/bcm2835: Remove buggy call to thermal_of_zone_unregister")
Cc [email protected]
Signed-off-by Krzysztof Kozlowski <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Daniel Lezcano <[email protected]>
drivers/thermal/broadcom/bcm2835_thermal.c +4 -15
index 5c1cebe07580..3b1030fc4fbf 100644
@@ -185,7 +185,7 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	data->clk = devm_clk_get(&pdev->dev, NULL);
+	data->clk = devm_clk_get_enabled(&pdev->dev, NULL);
 	if (IS_ERR(data->clk)) {
 		err = PTR_ERR(data->clk);
 		if (err != -EPROBE_DEFER)

@@ -193,10 +193,6 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	err = clk_prepare_enable(data->clk);
-	if (err)
-		return err;
-
 	rate = clk_get_rate(data->clk);
 	if ((rate < 1920000) || (rate > 5000000))
 		dev_warn(&pdev->dev,

@@ -211,7 +207,7 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev,
 			"Failed to register the thermal device: %d\n",
 			err);
-		goto err_clk;
+		return err;
 	}
 
 	/*

@@ -236,7 +232,7 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
 			dev_err(&pdev->dev,
 				"Not able to read trip_temp: %d\n",
 				err);
-			goto err_tz;
+			return err;
 		}
 
 		/* set bandgap reference voltage and enable voltage regulator */

@@ -269,17 +265,11 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
 	 */
 	err = thermal_add_hwmon_sysfs(tz);
 	if (err)
-		goto err_tz;
+		return err;
 
 	bcm2835_thermal_debugfs(pdev);
 
 	return 0;
-err_tz:
-	devm_thermal_of_zone_unregister(&pdev->dev, tz);
-err_clk:
-	clk_disable_unprepare(data->clk);
-
-	return err;
 }
 
 static void bcm2835_thermal_remove(struct platform_device *pdev)

@@ -287,7 +277,6 @@ static void bcm2835_thermal_remove(struct platform_device *pdev)
 	struct bcm2835_thermal_data *data = platform_get_drvdata(pdev);
 
 	debugfs_remove_recursive(data->debugfsdir);
-	clk_disable_unprepare(data->clk);
 }
 
 static struct platform_driver bcm2835_thermal_driver = {