Currently, the comments: "We can't create the thread unless interrupts
are enabled." from 'commit 4929c913bda5 ("rcu: Make call_rcu_tasks()
tolerate first call with irqs disabled")', now the kthread creation
has been move to core_initcall() time from 'commit c63eb17ff06d
("rcu: Create call_rcu_tasks() kthread at boot time")', and use the
irq_work does deferred wakeup. this commit therefore update comments
in call_rcu_tasks_generic().Signed-off-by: Zqiang <[email protected]> --- kernel/rcu/tasks.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index a2ca79d1dd6a..089a0d5a5cc9 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -395,7 +395,11 @@ static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func, raw_spin_unlock_irqrestore(&rtp->cbs_gbl_lock, flags); } rcu_read_unlock(); - /* We can't create the thread unless interrupts are enabled. */ + // We can't create the kthread with interrupts disabled, + // or a spinlock might be held, the kthread creation has + // been move to core_initcall() time. + // at the same time, use the irq_work does deferred wakeup + // to avoid potential lockdep splat. if (needwake && READ_ONCE(rtp->kthread_ptr)) irq_work_queue(&rtpcp->rtp_irq_work); } -- 2.17.1
