linux-kernel - [PATCH v7 03/17] of: overlay: add missing of_node_get() in __of_attach_node

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Message-Id: <1541743565-23163-4-git-send-email-frowand.list@gmail.com>
Date:   Thu,  8 Nov 2018 22:05:51 -0800
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 v7 03/17] 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.

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>
---
 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>