[PATCH 1/2] soc: samsung: exynos-pmu: fix of_node refcount leak in exynos_get_pmu_regmap()

[geoffrey]

From: Weigang He <geoffreyhe2 at gmail.com>

exynos_get_pmu_regmap() obtains a device_node via of_find_matching_node()
and passes it to exynos_get_pmu_regmap_by_phandle(np, NULL). With
propname == NULL the callee uses np directly and only drops a reference
when propname is set, so the reference taken by of_find_matching_node()
is leaked on every call -- including on each -EPROBE_DEFER retry of the
only in-tree caller, exynos_retention_init() in the Exynos pinctrl
driver.

Drop the reference in the function that acquired it.

Found by static analysis tool CodeQL.

Fixes: 76640b84bd7a ("soc: samsung: pmu: Provide global function to get PMU regmap")
Signed-off-by: Weigang He <geoffreyhe2 at gmail.com>
---
 drivers/soc/samsung/exynos-pmu.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c
index d58376c38179b..a5da2741852b4 100644
--- a/drivers/soc/samsung/exynos-pmu.c
+++ b/drivers/soc/samsung/exynos-pmu.c
@@ -167,11 +167,17 @@ static const struct mfd_cell exynos_pmu_devs[] = {
  */
 struct regmap *exynos_get_pmu_regmap(void)
 {
-	struct device_node *np = of_find_matching_node(NULL,
-						      exynos_pmu_of_device_ids);
-	if (np)
-		return exynos_get_pmu_regmap_by_phandle(np, NULL);
-	return ERR_PTR(-ENODEV);
+	struct device_node *np;
+	struct regmap *regmap;
+
+	np = of_find_matching_node(NULL, exynos_pmu_of_device_ids);
+	if (!np)
+		return ERR_PTR(-ENODEV);
+
+	regmap = exynos_get_pmu_regmap_by_phandle(np, NULL);
+	of_node_put(np);
+
+	return regmap;
 }
 EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap);
 
-- 
2.43.0