Commit 68230aac authored by Waiman Long's avatar Waiman Long Committed by Tejun Heo
Browse files

cgroup/cpuset: Fix incorrect use of cpuset_update_tasks_cpumask() in update_cpumasks_hier() 



Commit e2ffe502 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
incorrectly changed the 2nd parameter of cpuset_update_tasks_cpumask()
from tmp->new_cpus to cp->effective_cpus. This second parameter is just
a temporary cpumask for internal use. The cpuset_update_tasks_cpumask()
function was originally called update_tasks_cpumask() before commit
381b53c3 ("cgroup/cpuset: rename functions shared between v1
and v2").

This mistake can incorrectly change the effective_cpus of the
cpuset when it is the top_cpuset or in arm64 architecture where
task_cpu_possible_mask() may differ from cpu_possible_mask.  So far
top_cpuset hasn't been passed to update_cpumasks_hier() yet, but arm64
arch can still be impacted. Fix it by reverting the incorrect change.

Fixes: e2ffe502 ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent f9a1767c

kernel/cgroup/cpuset.c

+1 −1
Original line number Diff line number Diff line
@@ -2157,7 +2157,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, 
		WARN_ON(!is_in_v2_mode() &&

			!cpumask_equal(cp->cpus_allowed, cp->effective_cpus));



		cpuset_update_tasks_cpumask(cp, cp->effective_cpus);

		cpuset_update_tasks_cpumask(cp, tmp->new_cpus);



		/*

		 * On default hierarchy, inherit the CS_SCHED_LOAD_BALANCE