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of: drop a reference on error in __of_attach_node_sysfs()

PATCH In review Dan Carpenter 3 participants 4 messages May 18, 2020 – May 27, 2020

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Dan Carpenter

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#0 lore raw

PATCH 1/1 of: drop a reference on error in __of_attach_node_sysfs()

We add a new of_node_get() to this function, but we should drop the reference if kobject_add().

Fixes 5b2c2f5a0ea3 ("of: overlay: add missing of_node_get() in __of_attach_node_sysfs")
Signed-off-by Dan Carpenter <[email protected]>

---
From static analysis. Maybe we should just call of_node_get() right before we return 0?

 drivers/of/kobj.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
drivers/of/kobj.c +3 -1
index c72eef988041..a90dc4b3b060 100644
@@ -138,8 +138,10 @@ int __of_attach_node_sysfs(struct device_node *np)
 
 	rc = kobject_add(&np->kobj, parent, "%s", name);
 	kfree(name);
-	if (rc)
+	if (rc) {
+		of_node_put(np);
 		return rc;
+	}
 
 	for_each_property_of_node(np, pp)
 		__of_add_property_sysfs(np, pp);
Signature · 1 line
2.26.2
#1 lore raw
Quoted 2 lines · Dan Carpenter

We add a new of_node_get() to this function, but we should drop the reference if kobject_add().

                            ^
                            fails?
Quoted 6 lines
Fixes 5b2c2f5a0ea3 ("of: overlay: add missing of_node_get() in __of_attach_node_sysfs")
Signed-off-by Dan Carpenter <[email protected]>

---
From static analysis. Maybe we should just call of_node_get() right before we return 0?

Yeah that would be simpler and equally correct AFAICS.

cheers

Quoted 18 lines
drivers/of/kobj.c +3 -1
index c72eef988041..a90dc4b3b060 100644
@@ -138,8 +138,10 @@ int __of_attach_node_sysfs(struct device_node *np)
 
 	rc = kobject_add(&np->kobj, parent, "%s", name);
 	kfree(name);
-	if (rc)
+	if (rc) {
+		of_node_put(np);
 		return rc;
+	}
 
 	for_each_property_of_node(np, pp)
 		__of_add_property_sysfs(np, pp);
Signature · 1 line
2.26.2
author
#2 lore raw

PATCH v2 1/1 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 <[email protected]>

---
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(-)
drivers/of/kobj.c +1 -2
index c72eef988041..a32e60b024b8 100644
@@ -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;
 }
Signature · 1 line
2.26.2
maintainer Applied
#3 lore raw

Re: [PATCH v2] of: Fix a refcounting bug in __of_attach_node_sysfs()

Quoted 5 lines · Dan Carpenter

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.

Quoted 9 lines
Fixes 5b2c2f5a0ea3 ("of: overlay: add missing of_node_get() in __of_attach_node_sysfs")
Signed-off-by Dan Carpenter <[email protected]>

---
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(-)

Applied, thanks!