Commit 9137eda5 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'configfs-5.17-2022-02-25' of git://git.infradead.org/users/hch/configfs 

Pull configfs fix from Christoph Hellwig:

 - fix a race in configfs_{,un}register_subsystem (ChenXiaoSong)

* tag 'configfs-5.17-2022-02-25' of git://git.infradead.org/users/hch/configfs:
  configfs: fix a race in configfs_{,un}register_subsystem()
parents c0419188 84ec758f

fs/configfs/dir.c

+14 −0
Original line number Diff line number Diff line
@@ -34,6 +34,14 @@ 
 */

DEFINE_SPINLOCK(configfs_dirent_lock);



/*

 * All of link_obj/unlink_obj/link_group/unlink_group require that

 * subsys->su_mutex is held.

 * But parent configfs_subsystem is NULL when config_item is root.

 * Use this mutex when config_item is root.

 */

static DEFINE_MUTEX(configfs_subsystem_mutex);



static void configfs_d_iput(struct dentry * dentry,

			    struct inode * inode)

{
@@ -1859,7 +1867,9 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) 
		group->cg_item.ci_name = group->cg_item.ci_namebuf;



	sd = root->d_fsdata;

	mutex_lock(&configfs_subsystem_mutex);

	link_group(to_config_group(sd->s_element), group);

	mutex_unlock(&configfs_subsystem_mutex);



	inode_lock_nested(d_inode(root), I_MUTEX_PARENT);
@@ -1884,7 +1894,9 @@ int configfs_register_subsystem(struct configfs_subsystem *subsys) 
	inode_unlock(d_inode(root));



	if (err) {

		mutex_lock(&configfs_subsystem_mutex);

		unlink_group(group);

		mutex_unlock(&configfs_subsystem_mutex);

		configfs_release_fs();

	}

	put_fragment(frag);
@@ -1931,7 +1943,9 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys) 


	dput(dentry);



	mutex_lock(&configfs_subsystem_mutex);

	unlink_group(group);

	mutex_unlock(&configfs_subsystem_mutex);

	configfs_release_fs();

}