From 06f4e94898918bcad00cdd4d349313a439d6911e Mon Sep 17 00:00:00 2001 From: Zefan Li Date: Tue, 9 Aug 2016 11:25:01 +0800 Subject: [PATCH] cpuset: make sure new tasks conform to the current config of the cpuset A new task inherits cpus_allowed and mems_allowed masks from its parent, but if someone changes cpuset's config by writing to cpuset.cpus/cpuset.mems before this new task is inserted into the cgroup's task list, the new task won't be updated accordingly. Signed-off-by: Zefan Li Signed-off-by: Tejun Heo Cc: stable@vger.kernel.org --- kernel/cpuset.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/kernel/cpuset.c b/kernel/cpuset.c index c7fd2778ed50..c27e53326bef 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -2069,6 +2069,20 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css) mutex_unlock(&cpuset_mutex); } +/* + * Make sure the new task conform to the current state of its parent, + * which could have been changed by cpuset just after it inherits the + * state from the parent and before it sits on the cgroup's task list. + */ +void cpuset_fork(struct task_struct *task) +{ + if (task_css_is_root(task, cpuset_cgrp_id)) + return; + + set_cpus_allowed_ptr(task, ¤t->cpus_allowed); + task->mems_allowed = current->mems_allowed; +} + struct cgroup_subsys cpuset_cgrp_subsys = { .css_alloc = cpuset_css_alloc, .css_online = cpuset_css_online, @@ -2079,6 +2093,7 @@ struct cgroup_subsys cpuset_cgrp_subsys = { .attach = cpuset_attach, .post_attach = cpuset_post_attach, .bind = cpuset_bind, + .fork = cpuset_fork, .legacy_cftypes = files, .early_init = true, };