Commit 18966f7b authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Neeraj Upadhyay (AMD)
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rcu-tasks: Mark RCU Tasks accesses to current->rcu_tasks_idle_cpu 



The task_struct structure's ->rcu_tasks_idle_cpu can be concurrently
read and written from the RCU Tasks grace-period kthread and from the
CPU on which the task_struct structure's task is running.  This commit
therefore marks the accesses appropriately.

Reported-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Reviewed-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: default avatarNeeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
parent 98b1cc82

kernel/rcu/tasks.h

+2 −2
Original line number Diff line number Diff line
@@ -975,7 +975,7 @@ static void check_holdout_task(struct task_struct *t, 
	    t->rcu_tasks_nvcsw != READ_ONCE(t->nvcsw) ||

	    !rcu_tasks_is_holdout(t) ||

	    (IS_ENABLED(CONFIG_NO_HZ_FULL) &&

	     !is_idle_task(t) && t->rcu_tasks_idle_cpu >= 0)) {

	     !is_idle_task(t) && READ_ONCE(t->rcu_tasks_idle_cpu) >= 0)) {

		WRITE_ONCE(t->rcu_tasks_holdout, false);

		list_del_init(&t->rcu_tasks_holdout_list);

		put_task_struct(t);
@@ -993,7 +993,7 @@ static void check_holdout_task(struct task_struct *t, 
		 t, ".I"[is_idle_task(t)],

		 "N."[cpu < 0 || !tick_nohz_full_cpu(cpu)],

		 t->rcu_tasks_nvcsw, t->nvcsw, t->rcu_tasks_holdout,

		 t->rcu_tasks_idle_cpu, cpu);

		 data_race(t->rcu_tasks_idle_cpu), cpu);

	sched_show_task(t);

}