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Diffstat (limited to 'kernel/cgroup/cgroup.c')
-rw-r--r--kernel/cgroup/cgroup.c49
1 files changed, 30 insertions, 19 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 48851327a15e..c3c9a0e1b3c9 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -189,7 +189,7 @@ static u16 have_canfork_callback __read_mostly;
/* cgroup namespace for init task */
struct cgroup_namespace init_cgroup_ns = {
- .count = { .counter = 2, },
+ .count = REFCOUNT_INIT(2),
.user_ns = &init_user_ns,
.ns.ops = &cgroupns_operations,
.ns.inum = PROC_CGROUP_INIT_INO,
@@ -436,7 +436,12 @@ out_unlock:
return css;
}
-static void cgroup_get(struct cgroup *cgrp)
+static void __maybe_unused cgroup_get(struct cgroup *cgrp)
+{
+ css_get(&cgrp->self);
+}
+
+static void cgroup_get_live(struct cgroup *cgrp)
{
WARN_ON_ONCE(cgroup_is_dead(cgrp));
css_get(&cgrp->self);
@@ -554,7 +559,7 @@ EXPORT_SYMBOL_GPL(of_css);
* haven't been created.
*/
struct css_set init_css_set = {
- .refcount = ATOMIC_INIT(1),
+ .refcount = REFCOUNT_INIT(1),
.tasks = LIST_HEAD_INIT(init_css_set.tasks),
.mg_tasks = LIST_HEAD_INIT(init_css_set.mg_tasks),
.task_iters = LIST_HEAD_INIT(init_css_set.task_iters),
@@ -724,7 +729,7 @@ void put_css_set_locked(struct css_set *cset)
lockdep_assert_held(&css_set_lock);
- if (!atomic_dec_and_test(&cset->refcount))
+ if (!refcount_dec_and_test(&cset->refcount))
return;
/* This css_set is dead. unlink it and release cgroup and css refs */
@@ -932,7 +937,7 @@ static void link_css_set(struct list_head *tmp_links, struct css_set *cset,
list_add_tail(&link->cgrp_link, &cset->cgrp_links);
if (cgroup_parent(cgrp))
- cgroup_get(cgrp);
+ cgroup_get_live(cgrp);
}
/**
@@ -977,7 +982,7 @@ static struct css_set *find_css_set(struct css_set *old_cset,
return NULL;
}
- atomic_set(&cset->refcount, 1);
+ refcount_set(&cset->refcount, 1);
INIT_LIST_HEAD(&cset->tasks);
INIT_LIST_HEAD(&cset->mg_tasks);
INIT_LIST_HEAD(&cset->task_iters);
@@ -1640,7 +1645,7 @@ void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts)
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
}
-int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
+int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags)
{
LIST_HEAD(tmp_links);
struct cgroup *root_cgrp = &root->cgrp;
@@ -1656,8 +1661,8 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
root_cgrp->id = ret;
root_cgrp->ancestor_ids[0] = ret;
- ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release, 0,
- GFP_KERNEL);
+ ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release,
+ ref_flags, GFP_KERNEL);
if (ret)
goto out;
@@ -1802,7 +1807,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
return ERR_PTR(-EINVAL);
}
cgrp_dfl_visible = true;
- cgroup_get(&cgrp_dfl_root.cgrp);
+ cgroup_get_live(&cgrp_dfl_root.cgrp);
dentry = cgroup_do_mount(&cgroup2_fs_type, flags, &cgrp_dfl_root,
CGROUP2_SUPER_MAGIC, ns);
@@ -2425,11 +2430,12 @@ ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
tsk = tsk->group_leader;
/*
- * Workqueue threads may acquire PF_NO_SETAFFINITY and become
- * trapped in a cpuset, or RT worker may be born in a cgroup
- * with no rt_runtime allocated. Just say no.
+ * kthreads may acquire PF_NO_SETAFFINITY during initialization.
+ * If userland migrates such a kthread to a non-root cgroup, it can
+ * become trapped in a cpuset, or RT kthread may be born in a
+ * cgroup with no rt_runtime allocated. Just say no.
*/
- if (tsk == kthreadd_task || (tsk->flags & PF_NO_SETAFFINITY)) {
+ if (tsk->no_cgroup_migration || (tsk->flags & PF_NO_SETAFFINITY)) {
ret = -EINVAL;
goto out_unlock_rcu;
}
@@ -2575,7 +2581,7 @@ restart:
if (!css || !percpu_ref_is_dying(&css->refcnt))
continue;
- cgroup_get(dsct);
+ cgroup_get_live(dsct);
prepare_to_wait(&dsct->offline_waitq, &wait,
TASK_UNINTERRUPTIBLE);
@@ -3946,7 +3952,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css,
{
lockdep_assert_held(&cgroup_mutex);
- cgroup_get(cgrp);
+ cgroup_get_live(cgrp);
memset(css, 0, sizeof(*css));
css->cgroup = cgrp;
@@ -4122,7 +4128,7 @@ static struct cgroup *cgroup_create(struct cgroup *parent)
/* allocation complete, commit to creation */
list_add_tail_rcu(&cgrp->self.sibling, &cgroup_parent(cgrp)->self.children);
atomic_inc(&root->nr_cgrps);
- cgroup_get(parent);
+ cgroup_get_live(parent);
/*
* @cgrp is now fully operational. If something fails after this
@@ -4512,7 +4518,7 @@ int __init cgroup_init(void)
hash_add(css_set_table, &init_css_set.hlist,
css_set_hash(init_css_set.subsys));
- BUG_ON(cgroup_setup_root(&cgrp_dfl_root, 0));
+ BUG_ON(cgroup_setup_root(&cgrp_dfl_root, 0, 0));
mutex_unlock(&cgroup_mutex);
@@ -4946,7 +4952,7 @@ struct cgroup *cgroup_get_from_path(const char *path)
if (kn) {
if (kernfs_type(kn) == KERNFS_DIR) {
cgrp = kn->priv;
- cgroup_get(cgrp);
+ cgroup_get_live(cgrp);
} else {
cgrp = ERR_PTR(-ENOTDIR);
}
@@ -5026,6 +5032,11 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
/* Socket clone path */
if (skcd->val) {
+ /*
+ * We might be cloning a socket which is left in an empty
+ * cgroup and the cgroup might have already been rmdir'd.
+ * Don't use cgroup_get_live().
+ */
cgroup_get(sock_cgroup_ptr(skcd));
return;
}