Merge tag 'v3.12-rc4' into sched/core

[firefly-linux-kernel-4.4.55.git] / kernel / softirq.c

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 3e88612fc87e382b65663a3ffd6f13d0c27f2fb7..dcab1d3fb53d284cc42da1e36c6e5d001cd5baa9 100644 (file)
--- 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)