Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  tracing: Do not record user stack trace from NMI context
  tracing: Disable buffer switching when starting or stopping trace
  tracing: Use same local variable when resetting the ring buffer
  function-graph: Init curr_ret_stack with ret_stack
  ring-buffer: Move disabled check into preempt disable section
  function-graph: Add tracing_thresh support to function_graph tracer
  tracing: Update the comm field in the right variable in update_max_tr
  function-graph: Use comment notation for func names of dangling '}'
  function-graph: Fix unused reference to ftrace_set_func()
  tracing: Fix warning in s_next of trace file ops
  tracing: Include irqflags headers from trace clock

kernel/trace/ring_buffer.c

@@ -2233,12 +2233,12 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length)
 	if (ring_buffer_flags != RB_BUFFERS_ON)
 		return NULL;
 
-	if (atomic_read(&buffer->record_disabled))
-		return NULL;
-
 	/* If we are tracing schedule, we don't want to recurse */
 	resched = ftrace_preempt_disable();
 
+	if (atomic_read(&buffer->record_disabled))
+		goto out_nocheck;
+
 	if (trace_recursive_lock())
 		goto out_nocheck;
 
@@ -2470,11 +2470,11 @@ int ring_buffer_write(struct ring_buffer *buffer,
 	if (ring_buffer_flags != RB_BUFFERS_ON)
 		return -EBUSY;
 
-	if (atomic_read(&buffer->record_disabled))
-		return -EBUSY;
-
 	resched = ftrace_preempt_disable();
 
+	if (atomic_read(&buffer->record_disabled))
+		goto out;
+
 	cpu = raw_smp_processor_id();
 
 	if (!cpumask_test_cpu(cpu, buffer->cpumask))