Merge tag 'trace-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "This contains a few fixes and a clean up.

   - a bad merge caused an "endif" to go in the wrong place in
     scripts/Makefile.build

   - softirq tracing fix for tracing that corrupts lockdep and causes a
     false splat

   - histogram documentation typo fixes

   - fix a bad memory reference when passing in no filter to the filter
     code

   - simplify code by using the swap macro instead of open coding the
     swap"

* tag 'trace-v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix SKIP_STACK_VALIDATION=1 build due to bad merge with -mrecord-mcount
  tracing: Fix some errors in histogram documentation
  tracing: Use swap macro in update_max_tr
  softirq: Reorder trace_softirqs_on to prevent lockdep splat
  tracing: Check for no filter when processing event filters
update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
{
	int ret;

	if (tr->stop_count)
		return;

	WARN_ON_ONCE(!irqs_disabled());
	if (!tr->allocated_snapshot) {
		/* Only the nop tracer should hit this when disabling */
		WARN_ON_ONCE(tr->current_trace != &nop_trace);
		return;
	}

	arch_spin_lock(&tr->max_lock);

	ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);

	if (ret == -EBUSY) {
		/*
		 * We failed to swap the buffer due to a commit taking
		 * place on this CPU. We fail to record, but we reset
		 * the max trace buffer (no one writes directly to it)
		 * and flag that it failed.
		 */
		trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
			"Failed to swap buffers due to commit in progress\n");
	}

	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);

	__update_max_tr(tr, tsk, cpu);
	arch_spin_unlock(&tr->max_lock);
}

update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
{
	int ret;

	if (tr->stop_count)
		return;

	WARN_ON_ONCE(!irqs_disabled());
	if (!tr->allocated_snapshot) {
		/* Only the nop tracer should hit this when disabling */
		WARN_ON_ONCE(tr->current_trace != &nop_trace);
		return;
	}

	arch_spin_lock(&tr->max_lock);

	ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);

	if (ret == -EBUSY) {
		/*
		 * We failed to swap the buffer due to a commit taking
		 * place on this CPU. We fail to record, but we reset
		 * the max trace buffer (no one writes directly to it)
		 * and flag that it failed.
		 */
		trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
			"Failed to swap buffers due to commit in progress\n");
	}

	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);

	__update_max_tr(tr, tsk, cpu);
	arch_spin_unlock(&tr->max_lock);
}
