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-rw-r--r--kernel/rcu/update.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 3e888cd5a594..f0d8322bc3ec 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -528,6 +528,7 @@ static int rcu_task_stall_timeout __read_mostly = HZ * 60 * 10;
module_param(rcu_task_stall_timeout, int, 0644);
static void rcu_spawn_tasks_kthread(void);
+static struct task_struct *rcu_tasks_kthread_ptr;
/*
* Post an RCU-tasks callback. First call must be from process context
@@ -537,6 +538,7 @@ void call_rcu_tasks(struct rcu_head *rhp, rcu_callback_t func)
{
unsigned long flags;
bool needwake;
+ bool havetask = READ_ONCE(rcu_tasks_kthread_ptr);
rhp->next = NULL;
rhp->func = func;
@@ -545,7 +547,9 @@ void call_rcu_tasks(struct rcu_head *rhp, rcu_callback_t func)
*rcu_tasks_cbs_tail = rhp;
rcu_tasks_cbs_tail = &rhp->next;
raw_spin_unlock_irqrestore(&rcu_tasks_cbs_lock, flags);
- if (needwake) {
+ /* We can't create the thread unless interrupts are enabled. */
+ if ((needwake && havetask) ||
+ (!havetask && !irqs_disabled_flags(flags))) {
rcu_spawn_tasks_kthread();
wake_up(&rcu_tasks_cbs_wq);
}
@@ -790,7 +794,6 @@ static int __noreturn rcu_tasks_kthread(void *arg)
static void rcu_spawn_tasks_kthread(void)
{
static DEFINE_MUTEX(rcu_tasks_kthread_mutex);
- static struct task_struct *rcu_tasks_kthread_ptr;
struct task_struct *t;
if (READ_ONCE(rcu_tasks_kthread_ptr)) {