1 files changed, 14 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/powermac/pfunc_core.c b/arch/powerpc/platforms/powermac/pfunc_core.c
index f08173b0f065..047f954a89eb 100644
--- a/arch/powerpc/platforms/powermac/pfunc_core.c
+++ b/arch/powerpc/platforms/powermac/pfunc_core.c
@@ -871,10 +871,17 @@ int pmf_register_irq_client(struct device_node *target,
         spin_unlock_irqrestore(&pmf_lock, flags);
         if (func == NULL)
                 return -ENODEV;
+
+        /* guard against manipulations of list */
         mutex_lock(&pmf_irq_mutex);
         if (list_empty(&func->irq_clients))
                 func->dev->handlers->irq_enable(func);
+
+        /* guard against pmf_do_irq while changing list */
+        spin_lock_irqsave(&pmf_lock, flags);
         list_add(&client->link, &func->irq_clients);
+        spin_unlock_irqrestore(&pmf_lock, flags);
+
         client->func = func;
         mutex_unlock(&pmf_irq_mutex);
 
@@ -885,12 +892,19 @@ EXPORT_SYMBOL_GPL(pmf_register_irq_client);
 void pmf_unregister_irq_client(struct pmf_irq_client *client)
 {
         struct pmf_function *func = client->func;
+        unsigned long flags;
 
         BUG_ON(func == NULL);
 
+        /* guard against manipulations of list */
         mutex_lock(&pmf_irq_mutex);
         client->func = NULL;
+
+        /* guard against pmf_do_irq while changing list */
+        spin_lock_irqsave(&pmf_lock, flags);
         list_del(&client->link);
+        spin_unlock_irqrestore(&pmf_lock, flags);
+
         if (list_empty(&func->irq_clients))
                 func->dev->handlers->irq_disable(func);
         mutex_unlock(&pmf_irq_mutex);