As HK_TYPE_KERNEL_NOISE is going to be changeable at run time, use RCU to protect access to the cpumask when needed. Some access of the HK_TYPE_KERNEL_NOISE cpumask is done inside the tick code that has interrupt disabled which is a rcu_read_lock() critical section. Anyway, housekeeping_cpumask() will warn if they are used in invalid context.
Signed-off-by: Waiman Long <[email protected]> --- kernel/sched/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8952f5764517..6ae00c23d8a7 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1261,6 +1261,8 @@ int get_nohz_timer_target(void) struct sched_domain *sd; const struct cpumask *hk_mask; + guard(rcu)(); + if (housekeeping_cpu(cpu, HK_TYPE_KERNEL_NOISE)) { if (!idle_cpu(cpu)) return cpu; @@ -1269,8 +1271,6 @@ int get_nohz_timer_target(void) hk_mask = housekeeping_cpumask(HK_TYPE_KERNEL_NOISE); - guard(rcu)(); - for_each_domain(cpu, sd) { for_each_cpu_and(i, sched_domain_span(sd), hk_mask) { if (cpu == i) -- 2.53.0
