1 files changed, 12 insertions, 5 deletions

diff --git a/kernel/softirq.c b/kernel/softirq.c
index be3d3514c325..d7d498d8cc4f 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -328,10 +328,19 @@ void irq_enter(void)
 
 static inline void invoke_softirq(void)
 {
-        if (!force_irqthreads)
-                __do_softirq();
-        else
+        if (!force_irqthreads) {
+                /*
+                 * We can safely execute softirq on the current stack if
+                 * it is the irq stack, because it should be near empty
+                 * at this stage. But we have no way to know if the arch
+                 * calls irq_exit() on the irq stack. So call softirq
+                 * in its own stack to prevent from any overrun on top
+                 * of a potentially deep task stack.
+                 */
+                do_softirq();
+        } else {
                 wakeup_softirqd();
+        }
 }
 
 static inline void tick_irq_exit(void)
@@ -876,7 +885,6 @@ int __init __weak early_irq_init(void)
         return 0;
 }
 
-#ifdef CONFIG_GENERIC_HARDIRQS
 int __init __weak arch_probe_nr_irqs(void)
 {
         return NR_IRQS_LEGACY;
@@ -886,4 +894,3 @@ int __init __weak arch_early_irq_init(void)
 {
         return 0;
 }
-#endif