Re: [PATCH] kernel/sched: Fix sched_fork() access an invalid sched_task_group

[Tejun Heo]

Hello,

On Wed, Sep 08, 2021 at 07:32:06PM +0800, Zhang Qiao wrote:
> I will update this patch by following the steps below:
> 1)rename cgroup_subsys->fork() to cgroup_subsys->post_fork();
> 2)add cgroup_subsys->fork() and the cpu_cgroup_fork() callback like this:
> 
> void cpu_cgroup_fork(struct task_struct *task) {
> ....
> 	p->sched_task_group = task_group(current);
> 	__set_task_cpu(p, smp_processor_id());
> 	if (p->sched_class->task_fork)
> 		p->sched_class->task_fork(p);
> ....
> 
> 
> 3)call cgroup_subsys->fork() after cgroup_can_fork().
> 
> Do you have any suggestion?

I'm not following why it needs to shuffle the callbacks. Can't you just
relocate the fectching of task_group after can_fork?

Thanks.

-- 
tejun