Merge branch 'for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
"Nothing too exciting.
- updates to the pids controller so that pid limit breaches can be
noticed and monitored from userland.
- cleanups and non-critical bug fixes"
* 'for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: remove duplicated include from cgroup.c
cgroup: Use lld instead of ld when printing pids controller events_limit
cgroup: Add pids controller event when fork fails because of pid limit
cgroup: allow NULL return from ss->css_alloc()
cgroup: remove unnecessary 0 check from css_from_id()
cgroup: fix idr leak for the first cgroup root
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 75c0ff0..33a2f63 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -61,7 +61,6 @@
#include <linux/cpuset.h>
#include <linux/proc_ns.h>
#include <linux/nsproxy.h>
-#include <linux/proc_ns.h>
#include <net/sock.h>
/*
@@ -1160,18 +1159,12 @@
{
lockdep_assert_held(&cgroup_mutex);
- if (root->hierarchy_id) {
- idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
- root->hierarchy_id = 0;
- }
+ idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
}
static void cgroup_free_root(struct cgroup_root *root)
{
if (root) {
- /* hierarchy ID should already have been released */
- WARN_ON_ONCE(root->hierarchy_id);
-
idr_destroy(&root->cgroup_idr);
kfree(root);
}
@@ -5146,6 +5139,8 @@
lockdep_assert_held(&cgroup_mutex);
css = ss->css_alloc(parent_css);
+ if (!css)
+ css = ERR_PTR(-ENOMEM);
if (IS_ERR(css))
return css;
@@ -6172,7 +6167,7 @@
struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
{
WARN_ON_ONCE(!rcu_read_lock_held());
- return id > 0 ? idr_find(&ss->css_idr, id) : NULL;
+ return idr_find(&ss->css_idr, id);
}
/**
diff --git a/kernel/cgroup_pids.c b/kernel/cgroup_pids.c
index 303097b..2bd6737 100644
--- a/kernel/cgroup_pids.c
+++ b/kernel/cgroup_pids.c
@@ -49,6 +49,12 @@
*/
atomic64_t counter;
int64_t limit;
+
+ /* Handle for "pids.events" */
+ struct cgroup_file events_file;
+
+ /* Number of times fork failed because limit was hit. */
+ atomic64_t events_limit;
};
static struct pids_cgroup *css_pids(struct cgroup_subsys_state *css)
@@ -72,6 +78,7 @@
pids->limit = PIDS_MAX;
atomic64_set(&pids->counter, 0);
+ atomic64_set(&pids->events_limit, 0);
return &pids->css;
}
@@ -213,10 +220,21 @@
{
struct cgroup_subsys_state *css;
struct pids_cgroup *pids;
+ int err;
css = task_css_check(current, pids_cgrp_id, true);
pids = css_pids(css);
- return pids_try_charge(pids, 1);
+ err = pids_try_charge(pids, 1);
+ if (err) {
+ /* Only log the first time events_limit is incremented. */
+ if (atomic64_inc_return(&pids->events_limit) == 1) {
+ pr_info("cgroup: fork rejected by pids controller in ");
+ pr_cont_cgroup_path(task_cgroup(current, pids_cgrp_id));
+ pr_cont("\n");
+ }
+ cgroup_file_notify(&pids->events_file);
+ }
+ return err;
}
static void pids_cancel_fork(struct task_struct *task)
@@ -288,6 +306,14 @@
return atomic64_read(&pids->counter);
}
+static int pids_events_show(struct seq_file *sf, void *v)
+{
+ struct pids_cgroup *pids = css_pids(seq_css(sf));
+
+ seq_printf(sf, "max %lld\n", (s64)atomic64_read(&pids->events_limit));
+ return 0;
+}
+
static struct cftype pids_files[] = {
{
.name = "max",
@@ -300,6 +326,12 @@
.read_s64 = pids_current_read,
.flags = CFTYPE_NOT_ON_ROOT,
},
+ {
+ .name = "events",
+ .seq_show = pids_events_show,
+ .file_offset = offsetof(struct pids_cgroup, events_file),
+ .flags = CFTYPE_NOT_ON_ROOT,
+ },
{ } /* terminate */
};