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Commit 2378d8b8 authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarZefan Li <lizefan@huawei.com>
parent fa06235b

kernel/cgroup.c

+11 −4
Original line number Diff line number Diff line
@@ -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));