[PATCH v2 1/2] ftrace: Add check of sched_stopped for probe_sched_wakeup

[Zhaolei <zhaolei@cn.fujitsu.com>]

We need check sched_stopped in probe_sched_wakeup() to stop tracing when an
user stops it.

But current code can also do the right thing(stop tracing after
echo 0 > tracing_enabled) just because tracing_sched_wakeup_trace() can return
on buffer->record_disabled.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
---
 kernel/trace/trace_sched_switch.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index de35f20..9117cea 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -62,6 +62,9 @@ probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
 	pc = preempt_count();
 	tracing_record_cmdline(current);
 
+	if (sched_stopped)
+		return;
+
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = ctx_trace->data[cpu];
-- 
1.5.5.3