The task_struct structure's ->rcu_read_unlock_special field is only ever read or written by the owning task, but it is accessed both at process and interrupt levels. It may therefore be accessed using plain reads and writes while interrupts are disabled, but must be accessed using READ_ONCE() and WRITE_ONCE() or better otherwise. This commit makes a few adjustments to align with this discipline. Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx> --- kernel/rcu/tree_exp.h | 2 +- kernel/rcu/tree_plugin.h | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index ec4fb93a5dbe..1ee0782213b8 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -633,7 +633,7 @@ static void rcu_exp_handler(void *unused) raw_spin_lock_irqsave_rcu_node(rnp, flags); if (rnp->expmask & rdp->grpmask) { rdp->deferred_qs = true; - WRITE_ONCE(t->rcu_read_unlock_special.b.exp_hint, true); + t->rcu_read_unlock_special.b.exp_hint = true; } raw_spin_unlock_irqrestore_rcu_node(rnp, flags); return; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 81d3cd821891..6ddb3c05e88f 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -285,7 +285,7 @@ static void rcu_qs(void) TPS("cpuqs")); __this_cpu_write(rcu_data.cpu_no_qs.b.norm, false); barrier(); /* Coordinate with rcu_flavor_sched_clock_irq(). */ - current->rcu_read_unlock_special.b.need_qs = false; + WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, false); } } @@ -817,7 +817,7 @@ void exit_rcu(void) if (unlikely(!list_empty(¤t->rcu_node_entry))) { t->rcu_read_lock_nesting = 1; barrier(); - t->rcu_read_unlock_special.b.blocked = true; + WRITE_ONCE(t->rcu_read_unlock_special.b.blocked, true); } else if (unlikely(t->rcu_read_lock_nesting)) { t->rcu_read_lock_nesting = 1; } else { -- 2.17.1