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
8ae516aa8b