tracing: Only create tracer options files if directory exists

Do not bother creating tracer options if no tracing directory
exists. If a tracer is enabled via the command line, and is
started before the tracing directory is created, then it wont have
its tracer specific options created.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 38c613ede10d..d4627f15407a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4172,8 +4172,11 @@ static int tracing_set_tracer(struct trace_array *tr, const char *buf)
                 free_snapshot(tr);
         }
 #endif
-        /* Currently, only the top instance has options */
-        if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
+        /*
+         * Only enable if the directory has been created already.
+         * Currently, only the top instance has options
+         */
+        if (tr->dir && tr->flags & TRACE_ARRAY_FL_GLOBAL) {
                 destroy_trace_option_files(topts);
                 topts = create_trace_option_files(tr, t);
         }