[PATCH v2] cpufreq: OMAP: Fix resource leak in probe error path and remove

[Haotian Zhang <vulab@iscas.ac.cn>]

The current omap_cpufreq_probe() uses regulator_get() to obtain the MPU
regulator but does not release it in omap_cpufreq_remove() or when
cpufreq_register_driver() fails.

Add the missing regulator_put() in the remove function and in the
error handling path of the probe function to prevent resource leaks.
Also ensure the mpu_reg pointer is set to NULL after release to avoid
dangling pointers.

Fixes: 53dfe8a884e6 ("cpufreq: OMAP: scale voltage along with frequency")
Suggested-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>

---
Changes in v2:
 - Revert to using regulator_get() instead of devm_regulator_get()
   to ensure immediate release of unusable regulators and
   safer handling of the global mpu_reg variable.
 - Add explicit regulator_put() in omap_cpufreq_remove().
 - Add error handling for cpufreq_register_driver() in probe.
---
 drivers/cpufreq/omap-cpufreq.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index bbb01d93b54b..b3d58090d202 100644
--- a/drivers/cpufreq/omap-cpufreq.c
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -151,6 +151,8 @@ static struct cpufreq_driver omap_driver = {
 
 static int omap_cpufreq_probe(struct platform_device *pdev)
 {
+	int ret;
+
 	mpu_dev = get_cpu_device(0);
 	if (!mpu_dev) {
 		pr_warn("%s: unable to get the MPU device\n", __func__);
@@ -174,12 +176,23 @@ static int omap_cpufreq_probe(struct platform_device *pdev)
 		}
 	}
 
-	return cpufreq_register_driver(&omap_driver);
+	ret = cpufreq_register_driver(&omap_driver);
+	if (ret) {
+		if (mpu_reg) {
+			regulator_put(mpu_reg);
+			mpu_reg = NULL;
+		}
+	}
+	return ret;
 }
 
 static void omap_cpufreq_remove(struct platform_device *pdev)
 {
 	cpufreq_unregister_driver(&omap_driver);
+	if (mpu_reg) {
+		regulator_put(mpu_reg);
+		mpu_reg = NULL;
+	}
 }
 
 static struct platform_driver omap_cpufreq_platdrv = {
-- 
2.43.0