Merge tag 'irq-urgent-2021-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fix from Ingo Molnar:
 "A change to robustify force-threaded IRQ handlers to always disable
  interrupts, plus a DocBook fix.

  The force-threaded IRQ handler change has been accelerated from the
  normal schedule of such a change to keep the bad pattern/workaround of
  spin_lock_irqsave() in handlers or IRQF_NOTHREAD as a kludge from
  spreading"

* tag 'irq-urgent-2021-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Disable interrupts for force threaded handlers
  genirq/irq_sim: Fix typos in kernel doc (fnode -> fwnode)

Author: torvalds

kernel/irq/irq_sim.c

@@ -159,7 +159,7 @@ static const struct irq_domain_ops irq_sim_domain_ops = {
  * irq_domain_create_sim - Create a new interrupt simulator irq_domain and
  *                         allocate a range of dummy interrupts.
  *
- * @fnode:      struct fwnode_handle to be associated with this domain.
+ * @fwnode:     struct fwnode_handle to be associated with this domain.
  * @num_irqs:   Number of interrupts to allocate.
  *
  * On success: return a new irq_domain object.
@@ -228,7 +228,7 @@ static void devm_irq_domain_release_sim(struct device *dev, void *res)
  *                              a managed device.
  *
  * @dev:        Device to initialize the simulator object for.
- * @fnode:      struct fwnode_handle to be associated with this domain.
+ * @fwnode:     struct fwnode_handle to be associated with this domain.
  * @num_irqs:   Number of interrupts to allocate
  *
  * On success: return a new irq_domain object.

kernel/irq/manage.c

@@ -1142,11 +1142,15 @@ irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 	irqreturn_t ret;
 
 	local_bh_disable();
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		local_irq_disable();
 	ret = action->thread_fn(action->irq, action->dev_id);
 	if (ret == IRQ_HANDLED)
 		atomic_inc(&desc->threads_handled);
 
 	irq_finalize_oneshot(desc, action);
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		local_irq_enable();
 	local_bh_enable();
 	return ret;
 }