[PATCH 1/1] ftrace: fix function graph tracer

[Rajesh Bhagat]

when function tracer is set - function_graph tracer is not working
Problem occurs when CONFIG_DYNAMIC_FTRACE is not set

Output before patch
/debug/tracing # echo function > current_tracer
/debug/tracing # echo function_graph > current_tracer
/debug/tracing # cat trace

Output after patch
/debug/tracing # echo function > current_tracer
/debug/tracing # echo function_graph > current_tracer
/debug/tracing # cat trace
0) ! 253.375 us | } /* irq_enter */
0) | generic_handle_irq() {
0) | handle_fasteoi_irq() {
0) 9.208 us | _raw_spin_lock();
0) | handle_irq_event() {
0) | handle_irq_event_percpu() {

Signed-off-by: Rajesh Bhagat <rajesh.lnx@xxxxxxxxx>
---
 kernel/trace/ftrace.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 683d559..dc2de98 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -219,7 +219,8 @@ static void update_ftrace_function(void)
 #else
    __ftrace_trace_function = func;
 #endif
-   ftrace_trace_function = ftrace_test_stop_func;
+   ftrace_trace_function =
+       (func == ftrace_stub) ? func : ftrace_test_stop_func;
 #endif
 }
-- 
1.7.6
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