kobject: fix kset_find_obj() race with concurrent last kobject_put()

[mirror_ubuntu-artful-kernel.git] / lib / kobject.c

diff --git a/lib/kobject.c b/lib/kobject.c
index e07ee1fcd6f19da086439ffbeacd8376e4b3e533..a65486613d79775bf87918b390d8edd608d55cef 100644 (file)
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -529,6 +529,13 @@ struct kobject *kobject_get(struct kobject *kobj)
        return kobj;
 }
 
+static struct kobject *kobject_get_unless_zero(struct kobject *kobj)
+{
+       if (!kref_get_unless_zero(&kobj->kref))
+               kobj = NULL;
+       return kobj;
+}
+
 /*
  * kobject_cleanup - free kobject resources.
  * @kobj: object to cleanup
@@ -751,7 +758,7 @@ struct kobject *kset_find_obj(struct kset *kset, const char *name)
 
        list_for_each_entry(k, &kset->list, entry) {
                if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
-                       ret = kobject_get(k);
+                       ret = kobject_get_unless_zero(k);
                        break;
                }
        }