diff --git a/kernel/cpu.c b/kernel/cpu.c index 98a7a7b1471b7..f8eb1825f704f 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1215,8 +1215,22 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, return ret; } +struct cpu_down_work { + unsigned int cpu; + enum cpuhp_state target; +}; + +static long __cpu_down_maps_locked(void *arg) +{ + struct cpu_down_work *work = arg; + + return _cpu_down(work->cpu, 0, work->target); +} + static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) { + struct cpu_down_work work = { .cpu = cpu, .target = target, }; + /* * If the platform does not support hotplug, report it explicitly to * differentiate it from a transient offlining failure. @@ -1225,7 +1239,15 @@ static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) return -EOPNOTSUPP; if (cpu_hotplug_disabled) return -EBUSY; - return _cpu_down(cpu, 0, target); + + /* + * Ensure that the control task does not run on the to be offlined + * CPU to prevent a deadlock against cfs_b->period_timer. + */ + cpu = cpumask_any_but(cpu_online_mask, cpu); + if (cpu >= nr_cpu_ids) + return -EBUSY; + return work_on_cpu(cpu, __cpu_down_maps_locked, &work); } static int cpu_down(unsigned int cpu, enum cpuhp_state target)