#include <linux/file.h>
#include <net/sock.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/cgroup.h>
+
/*
* pidlists linger the following amount before being destroyed. The goal
* is avoiding frequent destruction in the middle of consecutive read calls
struct cgroup *cgrp = &root->cgrp;
struct cgrp_cset_link *link, *tmp_link;
+ trace_cgroup_destroy_root(root);
+
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
BUG_ON(atomic_read(&root->nr_cgrps));
strcpy(root->release_agent_path, opts.release_agent);
spin_unlock(&release_agent_path_lock);
}
+
+ trace_cgroup_remount(root);
+
out_unlock:
kfree(opts.release_agent);
kfree(opts.name);
if (ret)
goto destroy_root;
+ trace_cgroup_setup_root(root);
+
/*
* There must be no failure case after here, since rebinding takes
* care of subsystems' refcounts, which are explicitly dropped in
.fs_flags = FS_USERNS_MOUNT,
};
-static char *cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
- struct cgroup_namespace *ns)
+static int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
{
struct cgroup *root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
- int ret;
- ret = kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
- if (ret < 0 || ret >= buflen)
- return NULL;
- return buf;
+ return kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
}
-char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
- struct cgroup_namespace *ns)
+int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
{
- char *ret;
+ int ret;
mutex_lock(&cgroup_mutex);
spin_lock_irq(&css_set_lock);
*
* Return value is the same as kernfs_path().
*/
-char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
+int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
{
struct cgroup_root *root;
struct cgroup *cgrp;
int hierarchy_id = 1;
- char *path = NULL;
+ int ret;
mutex_lock(&cgroup_mutex);
spin_lock_irq(&css_set_lock);
if (root) {
cgrp = task_cgroup_from_root(task, root);
- path = cgroup_path_ns_locked(cgrp, buf, buflen, &init_cgroup_ns);
+ ret = cgroup_path_ns_locked(cgrp, buf, buflen, &init_cgroup_ns);
} else {
/* if no hierarchy exists, everyone is in "/" */
- if (strlcpy(buf, "/", buflen) < buflen)
- path = buf;
+ ret = strlcpy(buf, "/", buflen);
}
spin_unlock_irq(&css_set_lock);
mutex_unlock(&cgroup_mutex);
- return path;
+ return ret;
}
EXPORT_SYMBOL_GPL(task_cgroup_path);
ret = cgroup_migrate(leader, threadgroup, dst_cgrp->root);
cgroup_migrate_finish(&preloaded_csets);
+
+ if (!ret)
+ trace_cgroup_attach_task(dst_cgrp, leader, threadgroup);
+
return ret;
}
* Except for the root, subtree_control must be zero for a cgroup
* with tasks so that child cgroups don't compete against tasks.
*/
- if (enable && cgroup_parent(cgrp) && !list_empty(&cgrp->cset_links)) {
- ret = -EBUSY;
- goto out_unlock;
+ if (enable && cgroup_parent(cgrp)) {
+ struct cgrp_cset_link *link;
+
+ /*
+ * Because namespaces pin csets too, @cgrp->cset_links
+ * might not be empty even when @cgrp is empty. Walk and
+ * verify each cset.
+ */
+ spin_lock_irq(&css_set_lock);
+
+ ret = 0;
+ list_for_each_entry(link, &cgrp->cset_links, cset_link) {
+ if (css_set_populated(link->cset)) {
+ ret = -EBUSY;
+ break;
+ }
+ }
+
+ spin_unlock_irq(&css_set_lock);
+
+ if (ret)
+ goto out_unlock;
}
/* save and update control masks and prepare csses */
mutex_lock(&cgroup_mutex);
ret = kernfs_rename(kn, new_parent, new_name_str);
+ if (!ret)
+ trace_cgroup_rename(cgrp);
mutex_unlock(&cgroup_mutex);
* cgroup_task_count - count the number of tasks in a cgroup.
* @cgrp: the cgroup in question
*
- * Return the number of tasks in the cgroup.
+ * Return the number of tasks in the cgroup. The returned number can be
+ * higher than the actual number of tasks due to css_set references from
+ * namespace roots and temporary usages.
*/
static int cgroup_task_count(const struct cgroup *cgrp)
{
if (task) {
ret = cgroup_migrate(task, false, to->root);
+ if (!ret)
+ trace_cgroup_transfer_tasks(to, task, false);
put_task_struct(task);
}
} while (task && !ret);
ss->css_released(css);
} else {
/* cgroup release path */
+ trace_cgroup_release(cgrp);
+
cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id);
cgrp->id = -1;
if (ret)
goto out_destroy;
+ trace_cgroup_mkdir(cgrp);
+
/* let's create and online css's */
kernfs_activate(kn);
ret = cgroup_destroy_locked(cgrp);
+ if (!ret)
+ trace_cgroup_rmdir(cgrp);
+
cgroup_kn_unlock(kn);
return ret;
}
BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
+ /*
+ * The latency of the synchronize_sched() is too high for cgroups,
+ * avoid it at the cost of forcing all readers into the slow path.
+ */
+ rcu_sync_enter_start(&cgroup_threadgroup_rwsem.rss);
+
get_user_ns(init_cgroup_ns.user_ns);
mutex_lock(&cgroup_mutex);
int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *tsk)
{
- char *buf, *path;
+ char *buf;
int retval;
struct cgroup_root *root;
* " (deleted)" is appended to the cgroup path.
*/
if (cgroup_on_dfl(cgrp) || !(tsk->flags & PF_EXITING)) {
- path = cgroup_path_ns_locked(cgrp, buf, PATH_MAX,
+ retval = cgroup_path_ns_locked(cgrp, buf, PATH_MAX,
current->nsproxy->cgroup_ns);
- if (!path) {
+ if (retval >= PATH_MAX)
retval = -ENAMETOOLONG;
+ if (retval < 0)
goto out_unlock;
- }
+
+ seq_puts(m, buf);
} else {
- path = "/";
+ seq_puts(m, "/");
}
- seq_puts(m, path);
-
if (cgroup_on_dfl(cgrp) && cgroup_is_dead(cgrp))
seq_puts(m, " (deleted)\n");
else
{
struct cgroup *cgrp =
container_of(work, struct cgroup, release_agent_work);
- char *pathbuf = NULL, *agentbuf = NULL, *path;
+ char *pathbuf = NULL, *agentbuf = NULL;
char *argv[3], *envp[3];
+ int ret;
mutex_lock(&cgroup_mutex);
goto out;
spin_lock_irq(&css_set_lock);
- path = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX, &init_cgroup_ns);
+ ret = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX, &init_cgroup_ns);
spin_unlock_irq(&css_set_lock);
- if (!path)
+ if (ret < 0 || ret >= PATH_MAX)
goto out;
argv[0] = agentbuf;
- argv[1] = path;
+ argv[1] = pathbuf;
argv[2] = NULL;
/* minimal command environment */
/* cgroup namespaces */
+static struct ucounts *inc_cgroup_namespaces(struct user_namespace *ns)
+{
+ return inc_ucount(ns, current_euid(), UCOUNT_CGROUP_NAMESPACES);
+}
+
+static void dec_cgroup_namespaces(struct ucounts *ucounts)
+{
+ dec_ucount(ucounts, UCOUNT_CGROUP_NAMESPACES);
+}
+
static struct cgroup_namespace *alloc_cgroup_ns(void)
{
struct cgroup_namespace *new_ns;
void free_cgroup_ns(struct cgroup_namespace *ns)
{
put_css_set(ns->root_cset);
+ dec_cgroup_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
ns_free_inum(&ns->ns);
kfree(ns);
struct cgroup_namespace *old_ns)
{
struct cgroup_namespace *new_ns;
+ struct ucounts *ucounts;
struct css_set *cset;
BUG_ON(!old_ns);
if (!ns_capable(user_ns, CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);
+ ucounts = inc_cgroup_namespaces(user_ns);
+ if (!ucounts)
+ return ERR_PTR(-ENOSPC);
+
/* It is not safe to take cgroup_mutex here */
spin_lock_irq(&css_set_lock);
cset = task_css_set(current);
new_ns = alloc_cgroup_ns();
if (IS_ERR(new_ns)) {
put_css_set(cset);
+ dec_cgroup_namespaces(ucounts);
return new_ns;
}
new_ns->user_ns = get_user_ns(user_ns);
+ new_ns->ucounts = ucounts;
new_ns->root_cset = cset;
return new_ns;
put_cgroup_ns(to_cg_ns(ns));
}
+static struct user_namespace *cgroupns_owner(struct ns_common *ns)
+{
+ return to_cg_ns(ns)->user_ns;
+}
+
const struct proc_ns_operations cgroupns_operations = {
.name = "cgroup",
.type = CLONE_NEWCGROUP,
.get = cgroupns_get,
.put = cgroupns_put,
.install = cgroupns_install,
+ .owner = cgroupns_owner,
};
static __init int cgroup_namespaces_init(void)
projects / cascardo / linux.git / blobdiff