Expand the scope of cpuset_can_attach_check() by including the setting of setsched flag inside cpuset_can_attach_check() with the new @oldcs and @psetsched argument. As cpuset_can_attach_check() is also called from cpuset_can_fork(), set the new arguments to NULL from that caller.
Signed-off-by: Waiman Long <[email protected]> Reviewed-by: Ridong Chen <[email protected]> --- kernel/cgroup/cpuset.c | 52 ++++++++++++++++++++++++------------------ 1 file changed, 30 insertions(+), 22 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 1bcc3af77c94..05a81839966b 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3003,12 +3003,39 @@ static int update_prstate(struct cpuset *cs, int new_prs) * For v1, cpus_allowed and mems_allowed can't be empty. * For v2, effective_cpus can't be empty. * Note that in v1, effective_cpus = cpus_allowed. + * + * Also set the boolean flag passed in by @psetsched depending on if + * security_task_setscheduler() call is needed and @oldcs is not NULL. */ -static int cpuset_can_attach_check(struct cpuset *cs) +static int cpuset_can_attach_check(struct cpuset *cs, struct cpuset *oldcs, + bool *psetsched) { if (cpumask_empty(cs->effective_cpus) || (!is_in_v2_mode() && nodes_empty(cs->mems_allowed))) return -ENOSPC; + + if (!oldcs) + return 0; + + /* + * Skip rights over task setsched check in v2 when nothing changes, + * migration permission derives from hierarchy ownership in + * cgroup_procs_write_permission()). + */ + *psetsched = !cpuset_v2() || + !cpumask_equal(cs->effective_cpus, oldcs->effective_cpus) || + !nodes_equal(cs->effective_mems, oldcs->effective_mems); + + /* + * A v1 cpuset with tasks will have no CPU left only when CPU hotplug + * brings the last online CPU offline as users are not allowed to empty + * cpuset.cpus when there are active tasks inside. When that happens, + * we should allow tasks to migrate out without security check to make + * sure they will be able to run after migration. + */ + if (!is_in_v2_mode() && cpumask_empty(oldcs->effective_cpus)) + *psetsched = false; + return 0; } @@ -3055,29 +3082,10 @@ static int cpuset_can_attach(struct cgroup_taskset *tset) mutex_lock(&cpuset_mutex); /* Check to see if task is allowed in the cpuset */ - ret = cpuset_can_attach_check(cs); + ret = cpuset_can_attach_check(cs, oldcs, &setsched_check); if (ret) goto out_unlock; - /* - * Skip rights over task setsched check in v2 when nothing changes, - * migration permission derives from hierarchy ownership in - * cgroup_procs_write_permission()). - */ - setsched_check = !cpuset_v2() || - !cpumask_equal(cs->effective_cpus, oldcs->effective_cpus) || - !nodes_equal(cs->effective_mems, oldcs->effective_mems); - - /* - * A v1 cpuset with tasks will have no CPU left only when CPU hotplug - * brings the last online CPU offline as users are not allowed to empty - * cpuset.cpus when there are active tasks inside. When that happens, - * we should allow tasks to migrate out without security check to make - * sure they will be able to run after migration. - */ - if (!is_in_v2_mode() && cpumask_empty(oldcs->effective_cpus)) - setsched_check = false; - cgroup_taskset_for_each(task, css, tset) { ret = task_can_attach(task); if (ret) @@ -3631,7 +3639,7 @@ static int cpuset_can_fork(struct task_struct *task, struct css_set *cset) mutex_lock(&cpuset_mutex); /* Check to see if task is allowed in the cpuset */ - ret = cpuset_can_attach_check(cs); + ret = cpuset_can_attach_check(cs, NULL, NULL); if (ret) goto out_unlock; -- 2.54.0
