linux-kernel - [PATCH 4.19 70/74] of: overlay: add missing of_node_get() in __of_attach_node

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Date:   Mon,  4 Feb 2019 11:37:23 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Alan Tull <atull@...nel.org>,
        Frank Rowand <frank.rowand@...y.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.19 70/74] of: overlay: add missing of_node_get() in __of_attach_node_sysfs

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

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

commit 5b2c2f5a0ea3a43e0dee78059e34c7cb54136dcc upstream.

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.

This commit 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 commit will fix the leak.

Tested-by: Alan Tull <atull@...nel.org>
Acked-by: Michael Ellerman <mpe@...erman.id.au> (powerpc)
Signed-off-by: Frank Rowand <frank.rowand@...y.com>
Cc: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

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

--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -275,9 +275,6 @@ void __of_detach_node(struct device_node
 
 /**
  * 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)
 {
--- a/drivers/of/kobj.c
+++ b/drivers/of/kobj.c
@@ -133,6 +133,9 @@ int __of_attach_node_sysfs(struct device
 	}
 	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 devic
 		kobject_del(&np->kobj);
 	}
 
-	/* finally remove the kobj_init ref */
 	of_node_put(np);
 }