Unverified Commit 06ea25a8 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!1966 cpu/hotplug: Prevent self deadlock on CPU hot-unplug 

Merge Pull Request from: @ci-robot 
 
PR sync from: Yu Liao <liaoyu15@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/DBGRKXRT4RRBYG46MWMZ743SBDVUTBHT/ 
 
https://gitee.com/openeuler/kernel/issues/I7Y6AQ 
 
Link:https://gitee.com/openeuler/kernel/pulls/1966

 

Reviewed-by: default avatarXiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: default avatarJialin Zhang <zhangjialin11@huawei.com>
parents 0a41c492 4347224d

kernel/cpu.c

+23 −1
Original line number Diff line number Diff line
@@ -1112,11 +1112,33 @@ 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 (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)