nilfs2: fix NULL pointer in nilfs_##name##_attr_release

In nilfs_##name##_attr_release, kobj->parent should not be referenced because it is a NULL pointer. The release() method of kobject is always called in kobject_put(kobj), in the implementation of kobject_put(), the kobj->parent will be assigned as NULL before call the release() method. So just use kobj to get the subgroups, which is more efficient and can fix a NULL pointer reference problem. Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Nanyong Sun <[email protected]> Signed-off-by: Ryusuke Konishi <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
Axel1400 · Sep 8, 2021 · dbc6e7d · dbc6e7d
1 parent 5f5dec0
commit dbc6e7d
Showing 1 changed file with 3 additions and 5 deletions.
diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
@@ -51,11 +51,9 @@ static const struct sysfs_ops nilfs_##name##_attr_ops = { \
 #define NILFS_DEV_INT_GROUP_TYPE(name, parent_name) \
 static void nilfs_##name##_attr_release(struct kobject *kobj) \
 { \
-	struct nilfs_sysfs_##parent_name##_subgroups *subgroups; \
-	struct the_nilfs *nilfs = container_of(kobj->parent, \
-						struct the_nilfs, \
-						ns_##parent_name##_kobj); \
-	subgroups = nilfs->ns_##parent_name##_subgroups; \
+	struct nilfs_sysfs_##parent_name##_subgroups *subgroups = container_of(kobj, \
+						struct nilfs_sysfs_##parent_name##_subgroups, \
+						sg_##name##_kobj); \
 	complete(&subgroups->sg_##name##_kobj_unregister); \
 } \
 static struct kobj_type nilfs_##name##_ktype = { \