Commit 5f8bf2d2 authored Jul 15, 2014 by Steven Rostedt (Red Hat) Committed by Steven Rostedt Jul 15, 2014

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>

parent 8abfb872

kernel/trace/ftrace.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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.