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Commit 9609992d authored by Lingutla Chandrasekhar's avatar Lingutla Chandrasekhar
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Revert "driver core: fix race between creating/querying glue dir and its cleanup" 



This reverts 'commit 309a2c6f ("driver core: fix race between
creating/querying glue dir and its cleanup")'.

Issue is, if we fail the 'live_in_glue_dir' check on the dev->kobj, we'll
return NULL and subsequently fail to kobject_put the dev->kobj.parent in
the cleanup_glue_dir function, leaking a reference.

In upstream, this patch is modified to fix the leakage of glue_dir
parent. Get that change to avoid the kobject leakage.

Change-Id: I33f1c0c9471b97a9c77aa7ac068c01be95b0df94
Signed-off-by: default avatarLingutla Chandrasekhar <clingutla@codeaurora.org>
parent a4ced125

drivers/base/core.c

+10 −29
Original line number Diff line number Diff line
@@ -785,30 +785,12 @@ static struct kobject *get_device_parent(struct device *dev, 
		return &parent->kobj;

	return NULL;

}

static inline bool live_in_glue_dir(struct kobject *kobj,

					struct device *dev)

{

	if (!kobj || !dev->class ||

	    kobj->kset != &dev->class->p->glue_dirs)

		return false;

	return true;

}



static inline struct kobject *get_glue_dir(struct device *dev)

{

	if (live_in_glue_dir(&dev->kobj, dev))

		return dev->kobj.parent;

	return NULL;

}

/*

* make sure cleaning up dir as the last step, we need to make

* sure .release handler of kobject is run with holding the

* global lock

*/

static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)

{

	/* see if we live in a "glue" directory */

	if (!live_in_glue_dir(glue_dir, dev))

	if (!glue_dir || !dev->class ||

	    glue_dir->kset != &dev->class->p->glue_dirs)

		return;



	mutex_lock(&gdp_mutex);
@@ -816,6 +798,11 @@ static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir) 
	mutex_unlock(&gdp_mutex);

}



static void cleanup_device_parent(struct device *dev)

{

	cleanup_glue_dir(dev, dev->kobj.parent);

}



static int device_add_class_symlinks(struct device *dev)

{

	int error;
@@ -978,7 +965,6 @@ int device_add(struct device *dev) 
	struct device *parent = NULL;

	struct kobject *kobj;

	struct class_interface *class_intf;

	struct kobject *glue_dir = NULL;

	int error = -EINVAL;



	dev = get_device(dev);
@@ -1024,10 +1010,8 @@ int device_add(struct device *dev) 
	/* first, register with generic layer. */

	/* we require the name to be set before, and pass NULL */

	error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);

	if (error) {

		glue_dir = get_glue_dir(dev);

	if (error)

		goto Error;

	}



	/* notify platform of device entry */

	if (platform_notify)
@@ -1116,10 +1100,9 @@ done: 
	device_remove_file(dev, &dev_attr_uevent);

 attrError:

	kobject_uevent(&dev->kobj, KOBJ_REMOVE);

	glue_dir = get_glue_dir(dev);

	kobject_del(&dev->kobj);

 Error:

	cleanup_glue_dir(dev, glue_dir);

	cleanup_device_parent(dev);

	if (parent)

		put_device(parent);

name_error:
@@ -1196,7 +1179,6 @@ EXPORT_SYMBOL_GPL(put_device); 
void device_del(struct device *dev)

{

	struct device *parent = dev->parent;

	struct kobject *glue_dir = NULL;

	struct class_interface *class_intf;



	/* Notify clients of device removal.  This call must come
@@ -1241,9 +1223,8 @@ void device_del(struct device *dev) 
		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,

					     BUS_NOTIFY_REMOVED_DEVICE, dev);

	kobject_uevent(&dev->kobj, KOBJ_REMOVE);

	glue_dir = get_glue_dir(dev);

	cleanup_device_parent(dev);

	kobject_del(&dev->kobj);

	cleanup_glue_dir(dev, glue_dir);

	put_device(parent);

}

EXPORT_SYMBOL_GPL(device_del);