tracing: Fix graph tracer with stack tracer on other archs

Running my ftrace tests on PowerPC, it failed the test that checks
if function_graph tracer is affected by the stack tracer. It was.
Looking into this, I found that the update_function_graph_func()
must be called even if the trampoline function is not changed.
This is because archs like PowerPC do not support ftrace_ops being
passed by assembly and instead uses a helper function (what the
trampoline function points to). Since this function is not changed
even when multiple ftrace_ops are added to the code, the test that
falls out before calling update_function_graph_func() will miss that
the update must still be done.

Call update_function_graph_function() for all calls to
update_ftrace_function()

Cc: stable@vger.kernel.org # 3.3+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 5b372e3ed675..ac9d1dad630b 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -265,12 +265,12 @@ static void update_ftrace_function(void)
                 func = ftrace_ops_list_func;
         }
 
+        update_function_graph_func();
+
         /* If there's no change, then do nothing more here */
         if (ftrace_trace_function == func)
                 return;
 
-        update_function_graph_func();
-
         /*
          * If we are using the list function, it doesn't care
          * about the function_trace_ops.