From c87ab2ed2fa304fc54d01dbd6652776af18a172c Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Sun, 23 Nov 2008 17:33:12 +0100
Subject: [PATCH] --- yaml --- r: 121175 b: refs/heads/master c:
 eae849ca034c7f1015f0a6f17421ebc737f0a069 h: refs/heads/master i:   121173:
 44cdaf115835ca1ff51399b9a6a9f435792d91c0   121171:
 5f401bb37aed76eff62dd53647b7d55341bf983a   121167:
 0a4de6c5c9c9f3a5ef7c4306a682378a75437fc5 v: v3

---
 [refs]                      | 2 +-
 trunk/kernel/trace/ftrace.c | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 15e251c48b6c..f34642cf5fa3 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 82f60f0bc854aada696f27d863c03bef91f1509d
+refs/heads/master: eae849ca034c7f1015f0a6f17421ebc737f0a069
diff --git a/trunk/kernel/trace/ftrace.c b/trunk/kernel/trace/ftrace.c
index 90d99fb02ae4..53042f118f23 100644
--- a/trunk/kernel/trace/ftrace.c
+++ b/trunk/kernel/trace/ftrace.c
@@ -1628,8 +1628,13 @@ void ftrace_retfunc_init_task(struct task_struct *t)
 
 void ftrace_retfunc_exit_task(struct task_struct *t)
 {
-	kfree(t->ret_stack);
+	struct ftrace_ret_stack	*ret_stack = t->ret_stack;
+
 	t->ret_stack = NULL;
+	/* NULL must become visible to IRQs before we free it: */
+	barrier();
+
+	kfree(ret_stack);
 }
 #endif