diff options
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 9ceb93f848cd..21775eebb8f0 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1593,15 +1593,23 @@ static bool rcu_future_gp_cleanup(struct rcu_node *rnp) } /* - * Awaken the grace-period kthread. Don't do a self-awaken, and don't - * bother awakening when there is nothing for the grace-period kthread - * to do (as in several CPUs raced to awaken, and we lost), and finally - * don't try to awaken a kthread that has not yet been created. If - * all those checks are passed, track some debug information and awaken. + * Awaken the grace-period kthread. Don't do a self-awaken (unless in + * an interrupt or softirq handler), and don't bother awakening when there + * is nothing for the grace-period kthread to do (as in several CPUs raced + * to awaken, and we lost), and finally don't try to awaken a kthread that + * has not yet been created. If all those checks are passed, track some + * debug information and awaken. + * + * So why do the self-wakeup when in an interrupt or softirq handler + * in the grace-period kthread's context? Because the kthread might have + * been interrupted just as it was going to sleep, and just after the final + * pre-sleep check of the awaken condition. In this case, a wakeup really + * is required, and is therefore supplied. */ static void rcu_gp_kthread_wake(void) { - if (current == rcu_state.gp_kthread || + if ((current == rcu_state.gp_kthread && + !in_interrupt() && !in_serving_softirq()) || !READ_ONCE(rcu_state.gp_flags) || !rcu_state.gp_kthread) return; |