[PATCH] soc: samsung: exynos-pmu: fix reference leak in exynos_get_pmu_regmap_by_phandle()

[Ma Ke]

In exynos_get_pmu_regmap_by_phandle(), driver_find_device_by_of_node()
utilizes driver_find_device_by_fwnode() which internally calls
driver_find_device() to locate the matching device.
driver_find_device() increments the reference count of the found
device by calling get_device(), but exynos_get_pmu_regmap_by_phandle()
fails to call put_device() to decrement the reference count before
returning. This results in a reference count leak of the device each
time exynos_get_pmu_regmap_by_phandle() is executed, which may prevent
the device from being properly released and cause a memory leak.

Found by code review.

Cc: stable at vger.kernel.org
Fixes: 0b7c6075022c ("soc: samsung: exynos-pmu: Add regmap support for SoCs that protect PMU regs")
Signed-off-by: Ma Ke <make24 at iscas.ac.cn>
---
 drivers/soc/samsung/exynos-pmu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c
index a77288f49d24..ed903a2dd416 100644
--- a/drivers/soc/samsung/exynos-pmu.c
+++ b/drivers/soc/samsung/exynos-pmu.c
@@ -302,6 +302,7 @@ struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np,
 {
 	struct device_node *pmu_np;
 	struct device *dev;
+	struct regmap *regmap;
 
 	if (propname)
 		pmu_np = of_parse_phandle(np, propname, 0);
@@ -325,7 +326,10 @@ struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np,
 	if (!dev)
 		return ERR_PTR(-EPROBE_DEFER);
 
-	return syscon_node_to_regmap(pmu_np);
+	regmap = syscon_node_to_regmap(pmu_np);
+	put_device(regmap);
+
+	return regmap;
 }
 EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap_by_phandle);
 
-- 
2.17.1