Commit e6764aa0 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

Revert "kobject: Make sure the parent does not get released before its children" 



This reverts commit 4ef12f71.

Guenter reports:

	All my arm64be (arm64 big endian) boot tests crash with this
	patch applied. Reverting it fixes the problem. Crash log and
	bisect results (from pending-fixes branch) below.

And also:
	arm64 images don't crash but report lots of "poison overwritten"
	backtraces like the one below. On arm, I see "refcount_t:
	underflow", also attached.  I didn't bisect those, but given the
	context I would suspect the same culprit.

Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200513151840.36400-1-heikki.krogerus@linux.intel.com


Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Cc: kernel test robot <rong.a.chen@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4ef12f71

lib/kobject.c

+10 −20
Original line number Diff line number Diff line
@@ -599,7 +599,14 @@ out: 
}

EXPORT_SYMBOL_GPL(kobject_move);



static void __kobject_del(struct kobject *kobj)

/**

 * kobject_del() - Unlink kobject from hierarchy.

 * @kobj: object.

 *

 * This is the function that should be called to delete an object

 * successfully added via kobject_add().

 */

void kobject_del(struct kobject *kobj)

{

	struct kernfs_node *sd;

	const struct kobj_type *ktype;
@@ -618,23 +625,9 @@ static void __kobject_del(struct kobject *kobj) 


	kobj->state_in_sysfs = 0;

	kobj_kset_leave(kobj);

	kobject_put(kobj->parent);

	kobj->parent = NULL;

}



/**

 * kobject_del() - Unlink kobject from hierarchy.

 * @kobj: object.

 *

 * This is the function that should be called to delete an object

 * successfully added via kobject_add().

 */

void kobject_del(struct kobject *kobj)

{

	struct kobject *parent = kobj->parent;



	__kobject_del(kobj);

	kobject_put(parent);

}

EXPORT_SYMBOL(kobject_del);



/**
@@ -670,7 +663,6 @@ EXPORT_SYMBOL(kobject_get_unless_zero); 
 */

static void kobject_cleanup(struct kobject *kobj)

{

	struct kobject *parent = kobj->parent;

	struct kobj_type *t = get_ktype(kobj);

	const char *name = kobj->name;
@@ -692,7 +684,7 @@ static void kobject_cleanup(struct kobject *kobj) 
	if (kobj->state_in_sysfs) {

		pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",

			 kobject_name(kobj), kobj);

		__kobject_del(kobj);

		kobject_del(kobj);

	}



	if (t && t->release) {
@@ -706,8 +698,6 @@ static void kobject_cleanup(struct kobject *kobj) 
		pr_debug("kobject: '%s': free name\n", name);

		kfree_const(name);

	}



	kobject_put(parent);

}



#ifdef CONFIG_DEBUG_KOBJECT_RELEASE

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