Merge tag 'trace-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "This release has a few updates:

   - STM can hook into the function tracer
   - Function filtering now supports more advance glob matching
   - Ftrace selftests updates and added tests
   - Softirq tag in traces now show only softirqs
   - ARM nop added to non traced locations at compile time
   - New trace_marker_raw file that allows for binary input
   - Optimizations to the ring buffer
   - Removal of kmap in trace_marker
   - Wakeup and irqsoff tracers now adhere to the set_graph_notrace file
   - Other various fixes and clean ups"

* tag 'trace-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (42 commits)
  selftests: ftrace: Shift down default message verbosity
  kprobes/trace: Fix kprobe selftest for newer gcc
  tracing/kprobes: Add a helper method to return number of probe hits
  tracing/rb: Init the CPU mask on allocation
  tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate results
  tracing/fgraph: Have wakeup and irqsoff tracers ignore graph functions too
  fgraph: Handle a case where a tracer ignores set_graph_notrace
  tracing: Replace kmap with copy_from_user() in trace_marker writing
  ftrace/x86_32: Set ftrace_stub to weak to prevent gcc from using short jumps to it
  tracing: Allow benchmark to be enabled at early_initcall()
  tracing: Have system enable return error if one of the events fail
  tracing: Do not start benchmark on boot up
  tracing: Have the reg function allow to fail
  ring-buffer: Force rb_end_commit() and rb_set_commit_to_write() inline
  ring-buffer: Froce rb_update_write_stamp() to be inlined
  ring-buffer: Force inline of hotpath helper functions
  tracing: Make __buffer_unlock_commit() always_inline
  tracing: Make tracepoint_printk a static_key
  ring-buffer: Always inline rb_event_data()
  ring-buffer: Make rb_reserve_next_event() always inlined
  ...

1 files changed, 24 insertions, 2 deletions

diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
index 0f109c4130d3..e3b488825ae3 100644
--- a/kernel/trace/trace_benchmark.c
+++ b/kernel/trace/trace_benchmark.c
@@ -21,6 +21,8 @@ static u64 bm_stddev;
 static unsigned int bm_avg;
 static unsigned int bm_std;
 
+static bool ok_to_run;
+
 /*
  * This gets called in a loop recording the time it took to write
  * the tracepoint. What it writes is the time statistics of the last
@@ -164,11 +166,21 @@ static int benchmark_event_kthread(void *arg)
  * When the benchmark tracepoint is enabled, it calls this
  * function and the thread that calls the tracepoint is created.
  */
-void trace_benchmark_reg(void)
+int trace_benchmark_reg(void)
 {
+	if (!ok_to_run) {
+		pr_warning("trace benchmark cannot be started via kernel command line\n");
+		return -EBUSY;
+	}
+
 	bm_event_thread = kthread_run(benchmark_event_kthread,
 				      NULL, "event_benchmark");
-	WARN_ON(!bm_event_thread);
+	if (!bm_event_thread) {
+		pr_warning("trace benchmark failed to create kernel thread\n");
+		return -ENOMEM;
+	}
+
+	return 0;
 }
 
 /*
@@ -182,6 +194,7 @@ void trace_benchmark_unreg(void)
 		return;
 
 	kthread_stop(bm_event_thread);
+	bm_event_thread = NULL;
 
 	strcpy(bm_str, "START");
 	bm_total = 0;
@@ -196,3 +209,12 @@ void trace_benchmark_unreg(void)
 	bm_avg = 0;
 	bm_stddev = 0;
 }
+
+static __init int ok_to_run_trace_benchmark(void)
+{
+	ok_to_run = true;
+
+	return 0;
+}
+
+early_initcall(ok_to_run_trace_benchmark);