tracing/fgraph: Have wakeup and irqsoff tracers ignore graph functions too

Currently both the wakeup and irqsoff traces do not handle set_graph_notrace
well. The ftrace infrastructure will ignore the return paths of all
functions leaving them hanging without an end:

  # echo '*spin*' > set_graph_notrace
  # cat trace
  [...]
          _raw_spin_lock() {
            preempt_count_add() {
            do_raw_spin_lock() {
          update_rq_clock();

Where the '*spin*' functions should have looked like this:

          _raw_spin_lock() {
            preempt_count_add();
            do_raw_spin_lock();
          }
          update_rq_clock();

Instead, have the wakeup and irqsoff tracers ignore the functions that are
set by the set_graph_notrace like the function_graph tracer does. Move
the logic in the function_graph tracer into a header to allow wakeup and
irqsoff tracers to use it as well.

Cc: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 1bf2324dc682..5d0bb025bb21 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -239,6 +239,18 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
 	unsigned long flags;
 	int pc, ret = 0;
 
+	if (ftrace_graph_ignore_func(trace))
+		return 0;
+	/*
+	 * Do not trace a function if it's filtered by set_graph_notrace.
+	 * Make the index of ret stack negative to indicate that it should
+	 * ignore further functions.  But it needs its own ret stack entry
+	 * to recover the original index in order to continue tracing after
+	 * returning from the function.
+	 */
+	if (ftrace_graph_notrace_addr(trace->func))
+		return 1;
+
 	if (!func_prolog_preempt_disable(tr, &data, &pc))
 		return 0;