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thermal/drivers/broadcom: Fix race between removal and clock disable

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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: 8454c8c09c ("thermal/drivers/bcm2835: Remove buggy call to thermal_of_zone_unregister")
Cc: stable@vger.kernel.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240709-thermal-probe-v1-1-241644e2b6e0@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Krzysztof Kozlowski 2024-07-09 14:59:31 +02:00 committed by Daniel Lezcano
parent 6f48290b1a
commit e90c369cc2
1 changed files with 4 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/thermal/broadcom/bcm2835_thermal.c
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@ -185,7 +185,7 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
return err; return err;
} }
data->clk = devm_clk_get(&pdev->dev, NULL); data->clk = devm_clk_get_enabled(&pdev->dev, NULL);
if (IS_ERR(data->clk)) { if (IS_ERR(data->clk)) {
err = PTR_ERR(data->clk); err = PTR_ERR(data->clk);
if (err != -EPROBE_DEFER) if (err != -EPROBE_DEFER)
@ -193,10 +193,6 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
return err; return err;
} }
err = clk_prepare_enable(data->clk);
if (err)
return err;
rate = clk_get_rate(data->clk); rate = clk_get_rate(data->clk);
if ((rate < 1920000) || (rate > 5000000)) if ((rate < 1920000) || (rate > 5000000))
dev_warn(&pdev->dev, dev_warn(&pdev->dev,
@ -211,7 +207,7 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
dev_err(&pdev->dev, dev_err(&pdev->dev,
"Failed to register the thermal device: %d\n", "Failed to register the thermal device: %d\n",
err); err);
goto err_clk; return err;
} }
/* /*
@ -236,7 +232,7 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
dev_err(&pdev->dev, dev_err(&pdev->dev,
"Not able to read trip_temp: %d\n", "Not able to read trip_temp: %d\n",
err); err);
goto err_tz; return err;
} }
/* set bandgap reference voltage and enable voltage regulator */ /* 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); err = thermal_add_hwmon_sysfs(tz);
if (err) if (err)
goto err_tz; return err;
bcm2835_thermal_debugfs(pdev); bcm2835_thermal_debugfs(pdev);
return 0; 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) 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); struct bcm2835_thermal_data *data = platform_get_drvdata(pdev);
debugfs_remove_recursive(data->debugfsdir); debugfs_remove_recursive(data->debugfsdir);
clk_disable_unprepare(data->clk);
} }
static struct platform_driver bcm2835_thermal_driver = { static struct platform_driver bcm2835_thermal_driver = {