linux-kernel - [PATCH v2] of: Fix a refcounting bug in __of_attach_node

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Message-ID: <20200520120414.GE172354@mwanda>
Date:   Wed, 20 May 2020 15:04:14 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>
Cc:     Michael Ellerman <mpe@...erman.id.au>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH v2] of: Fix a refcounting bug in __of_attach_node_sysfs()

The problem in this code is that if kobject_add() fails, then it should
call of_node_put(np) to drop the reference count.  I've actually moved
the of_node_get(np) later in the function to avoid needing to do clean
up.

Fixes: 5b2c2f5a0ea3 ("of: overlay: add missing of_node_get() in __of_attach_node_sysfs")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
v2: move the of_node_get() instead of doing clean up.  Also the v1 had a
    confusing typo in the commit message.

 drivers/of/kobj.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/of/kobj.c b/drivers/of/kobj.c
index c72eef988041..a32e60b024b8 100644
--- a/drivers/of/kobj.c
+++ b/drivers/of/kobj.c
@@ -134,8 +134,6 @@ int __of_attach_node_sysfs(struct device_node *np)
 	if (!name)
 		return -ENOMEM;
 
-	of_node_get(np);
-
 	rc = kobject_add(&np->kobj, parent, "%s", name);
 	kfree(name);
 	if (rc)
@@ -144,6 +142,7 @@ int __of_attach_node_sysfs(struct device_node *np)
 	for_each_property_of_node(np, pp)
 		__of_add_property_sysfs(np, pp);
 
+	of_node_get(np);
 	return 0;
 }
 
-- 
2.26.2