linux-kernel - [PATCH v5 03/18] of: overlay: add missing of_node_get() in __of_attach_node

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Date:   Thu, 18 Oct 2018 15:46:21 -0700
From:   frowand.list@...il.com
To:     Rob Herring <robh+dt@...nel.org>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Alan Tull <atull@...nel.org>, Moritz Fischer <mdf@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        devicetree@...r.kernel.org, linux-fpga@...r.kernel.org
Subject: [PATCH v5 03/18] of: overlay: add missing of_node_get() in __of_attach_node_sysfs

From: Frank Rowand <frank.rowand@...y.com>

There is a matching of_node_put() in __of_detach_node_sysfs()

Remove misleading comment from function header comment for
of_detach_node().

This patch may result in memory leaks from code that directly calls
the dynamic node add and delete functions directly instead of
using changesets.

Signed-off-by: Frank Rowand <frank.rowand@...y.com>
---

This patch should result in powerpc systems that dynamically
allocate a node, then later deallocate the node to have a
memory leak when the node is deallocated.

The next patch in the series will fix the leak.

 drivers/of/dynamic.c | 3 ---
 drivers/of/kobj.c    | 4 +++-
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 12c3f9a15e94..146681540487 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -272,9 +272,6 @@ void __of_detach_node(struct device_node *np)
 
 /**
  * of_detach_node() - "Unplug" a node from the device tree.
- *
- * The caller must hold a reference to the node.  The memory associated with
- * the node is not freed until its refcount goes to zero.
  */
 int of_detach_node(struct device_node *np)
 {
diff --git a/drivers/of/kobj.c b/drivers/of/kobj.c
index 7a0a18980b98..c72eef988041 100644
--- a/drivers/of/kobj.c
+++ b/drivers/of/kobj.c
@@ -133,6 +133,9 @@ 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)
@@ -159,6 +162,5 @@ void __of_detach_node_sysfs(struct device_node *np)
 		kobject_del(&np->kobj);
 	}
 
-	/* finally remove the kobj_init ref */
 	of_node_put(np);
 }
-- 
Frank Rowand <frank.rowand@...y.com>