Merge tag 'trace-fixes-v3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull tracing fixes from Steven Rostedt:
 "This includes two fixes.

  1) is a bug fix that happens when root does the following:

     echo function_graph > current_tracer
     modprobe foo
     echo nop > current_tracer

   This causes the ftrace internal accounting to get screwed up and
   crashes ftrace, preventing the user from using the function tracer
   after that.

  2) if a TRACE_EVENT has a string field, and NULL is given for it.

   The internal trace event code does a strlen() and strcpy() on the
   source of field.  If it is NULL it causes the system to oops.

   This bug has been there since 2.6.31, but no TRACE_EVENT ever passed
   in a NULL to the string field, until now"

* tag 'trace-fixes-v3.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix function graph with loading of modules
  tracing: Allow events to have NULL strings