linux-kernel - [PATCH] powerpc: perf: Fix refcount leak bug in imc-pmu.c

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Date:   Sat, 18 Jun 2022 15:13:53 +0800
From:   Liang He <windhl@....com>
To:     mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
        atrajeev@...ux.vnet.ibm.com, christophe.leroy@...roup.eu
Cc:     windhl@....com, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] powerpc: perf: Fix refcount leak bug in imc-pmu.c

In update_events_in_group(), of_find_node_by_phandle() will return
a node pointer with refcount incremented. We should use of_node_put()
in fail path or when it is not used anymore.

Signed-off-by: Liang He <windhl@....com>
---
 arch/powerpc/perf/imc-pmu.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/perf/imc-pmu.c b/arch/powerpc/perf/imc-pmu.c
index d7976ab40d38..d517aba94d1b 100644
--- a/arch/powerpc/perf/imc-pmu.c
+++ b/arch/powerpc/perf/imc-pmu.c
@@ -240,8 +240,10 @@ static int update_events_in_group(struct device_node *node, struct imc_pmu *pmu)
 	ct = of_get_child_count(pmu_events);
 
 	/* Get the event prefix */
-	if (of_property_read_string(node, "events-prefix", &prefix))
+	if (of_property_read_string(node, "events-prefix", &prefix)) {
+		of_node_put(pmu_events);
 		return 0;
+	}
 
 	/* Get a global unit and scale data if available */
 	if (of_property_read_string(node, "scale", &g_scale))
@@ -255,8 +257,10 @@ static int update_events_in_group(struct device_node *node, struct imc_pmu *pmu)
 
 	/* Allocate memory for the events */
 	pmu->events = kcalloc(ct, sizeof(struct imc_events), GFP_KERNEL);
-	if (!pmu->events)
+	if (!pmu->events) {
+		of_node_put(pmu_events);
 		return -ENOMEM;
+	}
 
 	ct = 0;
 	/* Parse the events and update the struct */
@@ -266,6 +270,8 @@ static int update_events_in_group(struct device_node *node, struct imc_pmu *pmu)
 			ct++;
 	}
 
+	of_node_put(pmu_events);
+
 	/* Allocate memory for attribute group */
 	attr_group = kzalloc(sizeof(*attr_group), GFP_KERNEL);
 	if (!attr_group) {
-- 
2.25.1