Commit f60bf584 authored by Zheng Zucheng's avatar Zheng Zucheng Committed by Yang Yingliang
Browse files

sched: Fix offline task can't be killed in a timely 

hulk inclusion
category: bugfix
bugzilla: 51828, https://gitee.com/openeuler/kernel/issues/I4K96G


CVE: NA

--------------------------------

If online tasks occupy 100% CPU resources, offline tasks can't be scheduled
since offline tasks are throttled, as a result, offline task can't timely
respond after receiving SIGKILL signal.

Signed-off-by: default avatarZheng Zucheng <zhengzucheng@huawei.com>
Reviewed-by: default avatarXiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: default avatarChen Hui <judy.chenhui@huawei.com>
Reviewed-by: default avatarXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
parent 8ca949bd

include/linux/cgroup.h

+4 −0
Original line number Diff line number Diff line
@@ -886,4 +886,8 @@ static inline void put_cgroup_ns(struct cgroup_namespace *ns) 
		free_cgroup_ns(ns);

}



#ifdef CONFIG_QOS_SCHED

void cgroup_move_task_to_root(struct task_struct *tsk);

#endif



#endif /* _LINUX_CGROUP_H */

include/linux/sched.h

+4 −0
Original line number Diff line number Diff line
@@ -1951,4 +1951,8 @@ static inline void rseq_syscall(struct pt_regs *regs) 


#endif



#ifdef CONFIG_QOS_SCHED

void sched_move_offline_task(struct task_struct *p);

#endif



#endif

kernel/cgroup/cgroup.c

+22 −0
Original line number Diff line number Diff line
@@ -2719,6 +2719,28 @@ void cgroup_procs_write_finish(struct task_struct *task) 
			ss->post_attach();

}



#ifdef CONFIG_QOS_SCHED

void cgroup_move_task_to_root(struct task_struct *tsk)

{

	struct css_set *css;

	struct cgroup *cpu_cgrp;

	struct cgroup *cpu_root_cgrp;



	mutex_lock(&cgroup_mutex);

	percpu_down_write(&cgroup_threadgroup_rwsem);



	spin_lock_irq(&css_set_lock);

	css = task_css_set(tsk);

	cpu_cgrp = css->subsys[cpu_cgrp_id]->cgroup;

	cpu_root_cgrp = &cpu_cgrp->root->cgrp;

	spin_unlock_irq(&css_set_lock);



	(void)cgroup_attach_task(cpu_root_cgrp, tsk, false);

	percpu_up_write(&cgroup_threadgroup_rwsem);

	mutex_unlock(&cgroup_mutex);

}

#endif



static void cgroup_print_ss_mask(struct seq_file *seq, u16 ss_mask)

{

	struct cgroup_subsys *ss;

kernel/sched/core.c

+32 −0
Original line number Diff line number Diff line
@@ -6357,6 +6357,38 @@ static int alloc_qos_sched_group(struct task_group *tg, struct task_group *paren 


	return 1;

}



struct offline_args {

	struct work_struct work;

	struct task_struct *p;

};



static void sched_move_work(struct work_struct *work)

{

	struct sched_param param = { .sched_priority = 0 };

	struct offline_args *args = container_of(work, struct offline_args, work);



	cgroup_move_task_to_root(args->p);

	sched_setscheduler(args->p, SCHED_NORMAL, &param);

	put_task_struct(args->p);

	kfree(args);

}



void sched_move_offline_task(struct task_struct *p)

{

	struct offline_args *args;



	if (unlikely(task_group(p)->qos_level != -1))

		return;



	args = kmalloc(sizeof(struct offline_args), GFP_ATOMIC);

	if (args) {

		get_task_struct(p);

		args->p = p;

		INIT_WORK(&args->work, sched_move_work);

		queue_work(system_highpri_wq, &args->work);

	}

}

#endif



static void sched_free_group(struct task_group *tg)

kernel/signal.c

+3 −0
Original line number Diff line number Diff line
@@ -1040,6 +1040,9 @@ static void complete_signal(int sig, struct task_struct *p, enum pid_type type) 
			signal->group_stop_count = 0;

			t = p;

			do {

#ifdef CONFIG_QOS_SCHED

				sched_move_offline_task(t);

#endif

				task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);

				sigaddset(&t->pending.signal, SIGKILL);

				signal_wake_up(t, 1);