diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 98a8045..58c67b3 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2324,6 +2324,14 @@ static int cgroup_rename(struct kernfs_node *kn, struct kernfs_node *new_parent, if (cgroup_sane_behavior(cgrp)) return -EPERM; + /* + * We're gonna grab cgroup_tree_mutex which nests outside kernfs + * active_ref. kernfs_rename() doesn't require active_ref + * protection. Break them before grabbing cgroup_tree_mutex. + */ + kernfs_break_active_protection(new_parent); + kernfs_break_active_protection(kn); + mutex_lock(&cgroup_tree_mutex); mutex_lock(&cgroup_mutex); @@ -2331,6 +2339,9 @@ static int cgroup_rename(struct kernfs_node *kn, struct kernfs_node *new_parent, mutex_unlock(&cgroup_mutex); mutex_unlock(&cgroup_tree_mutex); + + kernfs_unbreak_active_protection(kn); + kernfs_unbreak_active_protection(new_parent); return ret; } @@ -3778,8 +3789,22 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode) { struct cgroup *parent = parent_kn->priv; + int ret; - return cgroup_create(parent, name, mode); + /* + * cgroup_create() grabs cgroup_tree_mutex which nests outside + * kernfs active_ref and cgroup_create() already synchronizes + * properly against removal through cgroup_lock_live_group(). + * Break it before calling cgroup_create(). + */ + cgroup_get(parent); + kernfs_break_active_protection(parent_kn); + + ret = cgroup_create(parent, name, mode); + + kernfs_unbreak_active_protection(parent_kn); + cgroup_put(parent); + return ret; } /* |
