trace-cmd: Fix record of function_graph

For safety reasons we always set ftrace_stack_trace to zero when
starting function tracer. But we seem to be doing that for
function_graph tracer as well, where that option does not exist.
Don't fail if it does not exist, quietly move on.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/trace-record.c b/trace-record.c
index 1ad1e19..58c9915 100644
--- a/trace-record.c
+++ b/trace-record.c
@@ -581,6 +581,8 @@ static void set_plugin(const char *name)
         path = tracecmd_get_tracing_file("options/func_stack_trace");
         fp = fopen(path, "w");
         tracecmd_put_tracing_file(path);
+        if (!fp)
+                return;
         fwrite(&zero, 1, 1, fp);
         fclose(fp);
 }