linux-kernel - [PATCH v2] powerpc: kernel: fix refcount leak in format

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Date:   Wed,  2 Mar 2022 10:19:59 +0800
From:   Hangyu Hua <hbh25y@...il.com>
To:     mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
        tyreld@...ux.ibm.com
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Hangyu Hua <hbh25y@...il.com>
Subject: [PATCH v2] powerpc: kernel: fix refcount leak in format_show()

Refcount leak will happen when format_show returns failure in multiple
cases. Unified management of of_node_put can fix this problem.

Signed-off-by: Hangyu Hua <hbh25y@...il.com>
---

v2: 
1. change the title and description information. 
2. fix all possible refcount leak.

 arch/powerpc/kernel/secvar-sysfs.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c
index a0a78aba2083..1ee4640a2641 100644
--- a/arch/powerpc/kernel/secvar-sysfs.c
+++ b/arch/powerpc/kernel/secvar-sysfs.c
@@ -26,15 +26,18 @@ static ssize_t format_show(struct kobject *kobj, struct kobj_attribute *attr,
 	const char *format;
 
 	node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend");
-	if (!of_device_is_available(node))
-		return -ENODEV;
+	if (!of_device_is_available(node)) {
+		rc = -ENODEV;
+		goto out;
+	}
 
 	rc = of_property_read_string(node, "format", &format);
 	if (rc)
-		return rc;
+		goto out;
 
 	rc = sprintf(buf, "%s\n", format);
 
+out:
 	of_node_put(node);
 
 	return rc;
-- 
2.25.1