From 2378d8b8ba3d2adffb4f98c0c60ee2f448b3be69 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 3 Mar 2016 09:57:57 -0500 Subject: [PATCH] cgroup: re-hash init_css_set after subsystems are initialized css_sets are hashed by their subsys[] contents and in cgroup_init() init_css_set is hashed early, before subsystem inits, when all entries in its subsys[] are NULL, so that cgroup_dfl_root initialization can find and link to it. As subsystems are initialized, init_css_set.subsys[] is filled up but the hashing is never updated making init_css_set hashed in the wrong place. While incorrect, this doesn't cause a critical failure as css_set management code would create an identical css_set dynamically. Fix it by rehashing init_css_set after subsystems are initialized. While at it, drop unnecessary @key local variable. Signed-off-by: Tejun Heo Acked-by: Zefan Li --- kernel/cgroup.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 46529502e9d5..e97772b42dfb 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5266,7 +5266,6 @@ static u16 cgroup_disable_mask __initdata; int __init cgroup_init(void) { struct cgroup_subsys *ss; - unsigned long key; int ssid; BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16); @@ -5276,9 +5275,12 @@ int __init cgroup_init(void) mutex_lock(&cgroup_mutex); - /* Add init_css_set to the hash table */ - key = css_set_hash(init_css_set.subsys); - hash_add(css_set_table, &init_css_set.hlist, key); + /* + * Add init_css_set to the hash table so that dfl_root can link to + * it during init. + */ + 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)); @@ -5331,6 +5333,11 @@ int __init cgroup_init(void) ss->bind(init_css_set.subsys[ssid]); } + /* init_css_set.subsys[] has been updated, re-hash */ + hash_del(&init_css_set.hlist); + hash_add(css_set_table, &init_css_set.hlist, + css_set_hash(init_css_set.subsys)); + WARN_ON(sysfs_create_mount_point(fs_kobj, "cgroup")); WARN_ON(register_filesystem(&cgroup_fs_type)); WARN_ON(register_filesystem(&cgroup2_fs_type)); -- 2.34.1