diff options
Diffstat (limited to 'kernel/kernel/cgroup.c')
| -rw-r--r-- | kernel/kernel/cgroup.c | 38 |
1 files changed, 31 insertions, 7 deletions
diff --git a/kernel/kernel/cgroup.c b/kernel/kernel/cgroup.c index a0087e536..af31510a2 100644 --- a/kernel/kernel/cgroup.c +++ b/kernel/kernel/cgroup.c @@ -236,6 +236,9 @@ static int cgroup_addrm_files(struct cgroup_subsys_state *css, */ static bool cgroup_ssid_enabled(int ssid) { + if (CGROUP_SUBSYS_COUNT == 0) + return false; + return static_key_enabled(cgroup_subsys_enabled_key[ssid]); } @@ -2498,6 +2501,14 @@ static void cgroup_migrate_add_src(struct css_set *src_cset, lockdep_assert_held(&cgroup_mutex); lockdep_assert_held(&css_set_lock); + /* + * If ->dead, @src_set is associated with one or more dead cgroups + * and doesn't contain any migratable tasks. Ignore it early so + * that the rest of migration path doesn't get confused by it. + */ + if (src_cset->dead) + return; + src_cgrp = cset_cgroup_from_root(src_cset, dst_cgrp->root); if (!list_empty(&src_cset->mg_preload_node)) @@ -2713,9 +2724,10 @@ static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off, bool threadgroup) { struct task_struct *tsk; + struct cgroup_subsys *ss; struct cgroup *cgrp; pid_t pid; - int ret; + int ssid, ret; if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0) return -EINVAL; @@ -2763,8 +2775,10 @@ out_unlock_rcu: rcu_read_unlock(); out_unlock_threadgroup: percpu_up_write(&cgroup_threadgroup_rwsem); + for_each_subsys(ss, ssid) + if (ss->post_attach) + ss->post_attach(); cgroup_kn_unlock(of->kn); - cpuset_post_attach_flush(); return ret ?: nbytes; } @@ -4681,14 +4695,15 @@ static void css_free_work_fn(struct work_struct *work) if (ss) { /* css free path */ + struct cgroup_subsys_state *parent = css->parent; int id = css->id; - if (css->parent) - css_put(css->parent); - ss->css_free(css); cgroup_idr_remove(&ss->css_idr, id); cgroup_put(cgrp); + + if (parent) + css_put(parent); } else { /* cgroup free path */ atomic_dec(&cgrp->root->nr_cgrps); @@ -4781,6 +4796,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css, memset(css, 0, sizeof(*css)); css->cgroup = cgrp; css->ss = ss; + css->id = -1; INIT_LIST_HEAD(&css->sibling); INIT_LIST_HEAD(&css->children); css->serial_nr = css_serial_nr_next++; @@ -5131,6 +5147,7 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) __releases(&cgroup_mutex) __acquires(&cgroup_mutex) { struct cgroup_subsys_state *css; + struct cgrp_cset_link *link; int ssid; lockdep_assert_held(&cgroup_mutex); @@ -5151,11 +5168,18 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) return -EBUSY; /* - * Mark @cgrp dead. This prevents further task migration and child - * creation by disabling cgroup_lock_live_group(). + * Mark @cgrp and the associated csets dead. The former prevents + * further task migration and child creation by disabling + * cgroup_lock_live_group(). The latter makes the csets ignored by + * the migration path. */ cgrp->self.flags &= ~CSS_ONLINE; + spin_lock_bh(&css_set_lock); + list_for_each_entry(link, &cgrp->cset_links, cset_link) + link->cset->dead = true; + spin_unlock_bh(&css_set_lock); + /* initiate massacre of all css's */ for_each_css(css, ssid, cgrp) kill_css(css); |