Merge tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Added new "bootconfig".

   This looks for a file appended to initrd to add boot config options,
   and has been discussed thoroughly at Linux Plumbers.

   Very useful for adding kprobes at bootup.

   Only enabled if "bootconfig" is on the real kernel command line.

 - Created dynamic event creation.

   Merges common code between creating synthetic events and kprobe
   events.

 - Rename perf "ring_buffer" structure to "perf_buffer"

 - Rename ftrace "ring_buffer" structure to "trace_buffer"

   Had to rename existing "trace_buffer" to "array_buffer"

 - Allow trace_printk() to work withing (some) tracing code.

 - Sort of tracing configs to be a little better organized

 - Fixed bug where ftrace_graph hash was not being protected properly

 - Various other small fixes and clean ups

* tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (88 commits)
  bootconfig: Show the number of nodes on boot message
  tools/bootconfig: Show the number of bootconfig nodes
  bootconfig: Add more parse error messages
  bootconfig: Use bootconfig instead of boot config
  ftrace: Protect ftrace_graph_hash with ftrace_sync
  ftrace: Add comment to why rcu_dereference_sched() is open coded
  tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu
  tracing: Annotate ftrace_graph_hash pointer with __rcu
  bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline
  tracing: Use seq_buf for building dynevent_cmd string
  tracing: Remove useless code in dynevent_arg_pair_add()
  tracing: Remove check_arg() callbacks from dynevent args
  tracing: Consolidate some synth_event_trace code
  tracing: Fix now invalid var_ref_vals assumption in trace action
  tracing: Change trace_boot to use synth_event interface
  tracing: Move tracing selftests to bottom of menu
  tracing: Move mmio tracer config up with the other tracers
  tracing: Move tracing test module configs together
  tracing: Move all function tracing configs together
  tracing: Documentation for in-kernel synthetic event API
  ...

1 files changed, 96 insertions, 10 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index fcd3975a88d1..f38234ecea18 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -238,7 +238,7 @@ bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 	if (!pid_list)
 		return false;
 
-	data = this_cpu_ptr(tr->trace_buffer.data);
+	data = this_cpu_ptr(tr->array_buffer.data);
 
 	return data->ignore_pid;
 }
@@ -273,6 +273,7 @@ void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 	if (!fbuffer->event)
 		return NULL;
 
+	fbuffer->regs = NULL;
 	fbuffer->entry = ring_buffer_event_data(fbuffer->event);
 	return fbuffer->entry;
 }
@@ -547,7 +548,7 @@ event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
 
 	pid_list = rcu_dereference_sched(tr->filtered_pids);
 
-	this_cpu_write(tr->trace_buffer.data->ignore_pid,
+	this_cpu_write(tr->array_buffer.data->ignore_pid,
 		       trace_ignore_this_task(pid_list, prev) &&
 		       trace_ignore_this_task(pid_list, next));
 }
@@ -561,7 +562,7 @@ event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
 
 	pid_list = rcu_dereference_sched(tr->filtered_pids);
 
-	this_cpu_write(tr->trace_buffer.data->ignore_pid,
+	this_cpu_write(tr->array_buffer.data->ignore_pid,
 		       trace_ignore_this_task(pid_list, next));
 }
 
@@ -572,12 +573,12 @@ event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 	struct trace_pid_list *pid_list;
 
 	/* Nothing to do if we are already tracing */
-	if (!this_cpu_read(tr->trace_buffer.data->ignore_pid))
+	if (!this_cpu_read(tr->array_buffer.data->ignore_pid))
 		return;
 
 	pid_list = rcu_dereference_sched(tr->filtered_pids);
 
-	this_cpu_write(tr->trace_buffer.data->ignore_pid,
+	this_cpu_write(tr->array_buffer.data->ignore_pid,
 		       trace_ignore_this_task(pid_list, task));
 }
 
@@ -588,13 +589,13 @@ event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 	struct trace_pid_list *pid_list;
 
 	/* Nothing to do if we are not tracing */
-	if (this_cpu_read(tr->trace_buffer.data->ignore_pid))
+	if (this_cpu_read(tr->array_buffer.data->ignore_pid))
 		return;
 
 	pid_list = rcu_dereference_sched(tr->filtered_pids);
 
 	/* Set tracing if current is enabled */
-	this_cpu_write(tr->trace_buffer.data->ignore_pid,
+	this_cpu_write(tr->array_buffer.data->ignore_pid,
 		       trace_ignore_this_task(pid_list, current));
 }
 
@@ -626,7 +627,7 @@ static void __ftrace_clear_event_pids(struct trace_array *tr)
 	}
 
 	for_each_possible_cpu(cpu)
-		per_cpu_ptr(tr->trace_buffer.data, cpu)->ignore_pid = false;
+		per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
 
 	rcu_assign_pointer(tr->filtered_pids, NULL);
 
@@ -1595,7 +1596,7 @@ static void ignore_task_cpu(void *data)
 	pid_list = rcu_dereference_protected(tr->filtered_pids,
 					     mutex_is_locked(&event_mutex));
 
-	this_cpu_write(tr->trace_buffer.data->ignore_pid,
+	this_cpu_write(tr->array_buffer.data->ignore_pid,
 		       trace_ignore_this_task(pid_list, current));
 }
 
@@ -2553,6 +2554,91 @@ find_event_file(struct trace_array *tr, const char *system, const char *event)
 	return file;
 }
 
+/**
+ * trace_get_event_file - Find and return a trace event file
+ * @instance: The name of the trace instance containing the event
+ * @system: The name of the system containing the event
+ * @event: The name of the event
+ *
+ * Return a trace event file given the trace instance name, trace
+ * system, and trace event name.  If the instance name is NULL, it
+ * refers to the top-level trace array.
+ *
+ * This function will look it up and return it if found, after calling
+ * trace_array_get() to prevent the instance from going away, and
+ * increment the event's module refcount to prevent it from being
+ * removed.
+ *
+ * To release the file, call trace_put_event_file(), which will call
+ * trace_array_put() and decrement the event's module refcount.
+ *
+ * Return: The trace event on success, ERR_PTR otherwise.
+ */
+struct trace_event_file *trace_get_event_file(const char *instance,
+					      const char *system,
+					      const char *event)
+{
+	struct trace_array *tr = top_trace_array();
+	struct trace_event_file *file = NULL;
+	int ret = -EINVAL;
+
+	if (instance) {
+		tr = trace_array_find_get(instance);
+		if (!tr)
+			return ERR_PTR(-ENOENT);
+	} else {
+		ret = trace_array_get(tr);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	mutex_lock(&event_mutex);
+
+	file = find_event_file(tr, system, event);
+	if (!file) {
+		trace_array_put(tr);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Don't let event modules unload while in use */
+	ret = try_module_get(file->event_call->mod);
+	if (!ret) {
+		trace_array_put(tr);
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ret = 0;
+ out:
+	mutex_unlock(&event_mutex);
+
+	if (ret)
+		file = ERR_PTR(ret);
+
+	return file;
+}
+EXPORT_SYMBOL_GPL(trace_get_event_file);
+
+/**
+ * trace_put_event_file - Release a file from trace_get_event_file()
+ * @file: The trace event file
+ *
+ * If a file was retrieved using trace_get_event_file(), this should
+ * be called when it's no longer needed.  It will cancel the previous
+ * trace_array_get() called by that function, and decrement the
+ * event's module refcount.
+ */
+void trace_put_event_file(struct trace_event_file *file)
+{
+	mutex_lock(&event_mutex);
+	module_put(file->event_call->mod);
+	mutex_unlock(&event_mutex);
+
+	trace_array_put(file->tr);
+}
+EXPORT_SYMBOL_GPL(trace_put_event_file);
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 /* Avoid typos */
@@ -3409,8 +3495,8 @@ static void __init
 function_test_events_call(unsigned long ip, unsigned long parent_ip,
 			  struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
+	struct trace_buffer *buffer;
 	struct ring_buffer_event *event;
-	struct ring_buffer *buffer;
 	struct ftrace_entry *entry;
 	unsigned long flags;
 	long disabled;