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Commit d030671f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 

Pull cgroup fixes from Tejun Heo:
 "This pull request includes Alban's patch to disallow '\n' in cgroup
  names.

  Two other patches from Li to fix a possible oops when cgroup
  destruction races against other file operations and one from Vivek to
  fix a unified hierarchy devel behavior"

* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: check cgroup liveliness before unbreaking kernfs
  cgroup: delay the clearing of cgrp->kn->priv
  cgroup: Display legacy cgroup files on default hierarchy
  cgroup: reject cgroup names with '\n'
parents 6a5c75ce aa32362f

kernel/cgroup.c

+33 −14
Original line number Diff line number Diff line
@@ -1035,6 +1035,11 @@ static void cgroup_get(struct cgroup *cgrp) 
	css_get(&cgrp->self);

}



static bool cgroup_tryget(struct cgroup *cgrp)

{

	return css_tryget(&cgrp->self);

}



static void cgroup_put(struct cgroup *cgrp)

{

	css_put(&cgrp->self);
@@ -1147,7 +1152,8 @@ static struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn) 
	 * protection against removal.  Ensure @cgrp stays accessible and

	 * break the active_ref protection.

	 */

	cgroup_get(cgrp);

	if (!cgroup_tryget(cgrp))

		return NULL;

	kernfs_break_active_protection(kn);



	mutex_lock(&cgroup_mutex);
@@ -3271,8 +3277,17 @@ int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts) 
{

	struct cftype *cft;



	/*

	 * If legacy_flies_on_dfl, we want to show the legacy files on the

	 * dfl hierarchy but iff the target subsystem hasn't been updated

	 * for the dfl hierarchy yet.

	 */

	if (!cgroup_legacy_files_on_dfl ||

	    ss->dfl_cftypes != ss->legacy_cftypes) {

		for (cft = cfts; cft && cft->name[0] != '\0'; cft++)

			cft->flags |= __CFTYPE_NOT_ON_DFL;

	}



	return cgroup_add_cftypes(ss, cfts);

}
@@ -4387,6 +4402,15 @@ static void css_release_work_fn(struct work_struct *work) 
		/* cgroup release path */

		cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id);

		cgrp->id = -1;



		/*

		 * There are two control paths which try to determine

		 * cgroup from dentry without going through kernfs -

		 * cgroupstats_build() and css_tryget_online_from_dir().

		 * Those are supported by RCU protecting clearing of

		 * cgrp->kn->priv backpointer.

		 */

		RCU_INIT_POINTER(*(void __rcu __force **)&cgrp->kn->priv, NULL);

	}



	mutex_unlock(&cgroup_mutex);
@@ -4543,6 +4567,11 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, 
	struct cftype *base_files;

	int ssid, ret;



	/* Do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable.

	 */

	if (strchr(name, '\n'))

		return -EINVAL;



	parent = cgroup_kn_lock_live(parent_kn);

	if (!parent)

		return -ENODEV;
@@ -4820,16 +4849,6 @@ static int cgroup_rmdir(struct kernfs_node *kn) 


	cgroup_kn_unlock(kn);



	/*

	 * There are two control paths which try to determine cgroup from

	 * dentry without going through kernfs - cgroupstats_build() and

	 * css_tryget_online_from_dir().  Those are supported by RCU

	 * protecting clearing of cgrp->kn->priv backpointer, which should

	 * happen after all files under it have been removed.

	 */

	if (!ret)

		RCU_INIT_POINTER(*(void __rcu __force **)&kn->priv, NULL);



	cgroup_put(cgrp);

	return ret;

}
@@ -5416,7 +5435,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, 
	/*

	 * This path doesn't originate from kernfs and @kn could already

	 * have been or be removed at any point.  @kn->priv is RCU

	 * protected for this access.  See cgroup_rmdir() for details.

	 * protected for this access.  See css_release_work_fn() for details.

	 */

	cgrp = rcu_dereference(kn->priv);

	if (cgrp)