tracing/kprobes: Avoid self tests if tracing is disabled on boot up

If tracing is disabled on boot up, the kernel should not execute tracing
self tests. The kernel should check whether tracing is disabled or not
before executing any of the tracing self tests.

Link: http://lkml.kernel.org/p/20140605223520.32311.56097.stgit@yunodevel
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 903ae28962be7f513c2a382631da4da2aeef377e..ef2fba1f46b598eae5c7462601a96d98f65ef322 100644 (file)
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1377,6 +1377,9 @@ static __init int kprobe_trace_self_tests_init(void)
        struct trace_kprobe *tk;
        struct ftrace_event_file *file;
 
+       if (tracing_is_disabled())
+               return -ENODEV;
+
        target = kprobe_trace_selftest_target;
 
        pr_info("Testing kprobe tracing: ");