Commit 4ef12f71 authored by Heikki Krogerus's avatar Heikki Krogerus Committed by Greg Kroah-Hartman

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

In the function kobject_cleanup(), kobject_del(kobj) is
called before the kobj->release(). That makes it possible to
release the parent of the kobject before the kobject itself.

To fix that, adding function __kboject_del() that does
everything that kobject_del() does except release the parent
reference. kobject_cleanup() then calls __kobject_del()
instead of kobject_del(), and separately decrements the
reference count of the parent kobject after kobj->release()
has been called.
Reported-by: default avatarNaresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: default avatarkernel test robot <rong.a.chen@intel.com>
Fixes: 7589238a ("Revert "software node: Simplify software_node_release() function"")
Suggested-by: default avatar"Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: default avatarBrendan Higgins <brendanhiggins@google.com>
Tested-by: default avatarBrendan Higgins <brendanhiggins@google.com>
Acked-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20200513151840.36400-1-heikki.krogerus@linux.intel.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 44e96049
...@@ -599,14 +599,7 @@ int kobject_move(struct kobject *kobj, struct kobject *new_parent) ...@@ -599,14 +599,7 @@ int kobject_move(struct kobject *kobj, struct kobject *new_parent)
} }
EXPORT_SYMBOL_GPL(kobject_move); 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; struct kernfs_node *sd;
const struct kobj_type *ktype; const struct kobj_type *ktype;
...@@ -625,9 +618,23 @@ void kobject_del(struct kobject *kobj) ...@@ -625,9 +618,23 @@ void kobject_del(struct kobject *kobj)
kobj->state_in_sysfs = 0; kobj->state_in_sysfs = 0;
kobj_kset_leave(kobj); kobj_kset_leave(kobj);
kobject_put(kobj->parent);
kobj->parent = NULL; 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); EXPORT_SYMBOL(kobject_del);
/** /**
...@@ -663,6 +670,7 @@ EXPORT_SYMBOL(kobject_get_unless_zero); ...@@ -663,6 +670,7 @@ EXPORT_SYMBOL(kobject_get_unless_zero);
*/ */
static void kobject_cleanup(struct kobject *kobj) static void kobject_cleanup(struct kobject *kobj)
{ {
struct kobject *parent = kobj->parent;
struct kobj_type *t = get_ktype(kobj); struct kobj_type *t = get_ktype(kobj);
const char *name = kobj->name; const char *name = kobj->name;
...@@ -684,7 +692,7 @@ static void kobject_cleanup(struct kobject *kobj) ...@@ -684,7 +692,7 @@ static void kobject_cleanup(struct kobject *kobj)
if (kobj->state_in_sysfs) { if (kobj->state_in_sysfs) {
pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n", pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
kobject_name(kobj), kobj); kobject_name(kobj), kobj);
kobject_del(kobj); __kobject_del(kobj);
} }
if (t && t->release) { if (t && t->release) {
...@@ -698,6 +706,8 @@ static void kobject_cleanup(struct kobject *kobj) ...@@ -698,6 +706,8 @@ static void kobject_cleanup(struct kobject *kobj)
pr_debug("kobject: '%s': free name\n", name); pr_debug("kobject: '%s': free name\n", name);
kfree_const(name); kfree_const(name);
} }
kobject_put(parent);
} }
#ifdef CONFIG_DEBUG_KOBJECT_RELEASE #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment