Re: [PATCH 1/3] task: Add a count of task rcu users
From: Oleg Nesterov
Date: Wed Sep 04 2019 - 10:36:40 EST
On 09/02, Eric W. Biederman wrote:
>
> @@ -900,10 +900,9 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
> - /*
> - * One for us, one for whoever does the "release_task()" (usually
> - * parent)
> - */
> + /* One for the user space visible state that goes away when reaped. */
> + refcount_set(&tsk->rcu_users, 1);
forgot to mention...
This is minor, but we don't really need to initialize child->rcu_users in
dup_task_struct(), we can just add
.rcu_users = REFCOUNT_INIT(2),
into init_task's initializer.
Until we have a refcount_inc(task->rcu_users) user, of course.
Oleg.