tracing: handle unregistering the current tracer

Impact: simplification

Instead of requiring that plugins have the sequence:

  my_tracer_stop(my_trace_array);
  unregister_tracer(my_tracer);

it should be possible just do a:

  unregister_tracer(my_tracer);

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 03fbd4c20bc2..93040f1bef13 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -559,6 +559,15 @@ void unregister_tracer(struct tracer *type)
 
  found:
         *t = (*t)->next;
+
+        if (type == current_trace && tracer_enabled) {
+                tracer_enabled = 0;
+                tracing_stop();
+                if (current_trace->stop)
+                        current_trace->stop(&global_trace);
+                current_trace = &nop_trace;
+        }
+
         if (strlen(type->name) != max_tracer_type_len)
                 goto out;