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'
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 7dc8788..940aced 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1035,6 +1035,11 @@
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 @@
* 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 @@
{
struct cftype *cft;
- for (cft = cfts; cft && cft->name[0] != '\0'; cft++)
- cft->flags |= __CFTYPE_NOT_ON_DFL;
+ /*
+ * 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 @@
/* 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 @@
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 @@
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 @@
/*
* 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)
