tracing/boot: Initialize per-instance event list in early boot

Initialize per-instance event list in early boot time (before initializing instance directory on tracefs). This fixes boot-time tracing to correctly handle the boot-time per-instance settings. Link: https://lkml.kernel.org/r/160096560826.182763.17110991546046128881.stgit@devnote2

Masami Hiramatsu committed 6 years ago

Commit 720dee51 parent fd264ce3 files · +19 −15Browse files

Unified · Split

3 files

kernel/trace/trace.c +2 −1
kernel/trace/trace.h +1 −0
kernel/trace/trace_events.c +16 −14

kernel/trace/trace.c+2−1

@@ -8700,7 +8700,8 @@ static struct trace_array trace_array_create(const char name) · 8699 unmodified lines
8700	ret = trace_array_create_dir(tr);	8700	ret = trace_array_create_dir(tr);
8701	if (ret)	8701	if (ret)
8702	goto out_free_tr;	8702	goto out_free_tr;
8703	}	8703	} else
		8704	__trace_early_add_events(tr);
8704		8705
8705	list_add(&tr->list, &ftrace_trace_arrays);	8706	list_add(&tr->list, &ftrace_trace_arrays);
8706		8707

kernel/trace/trace.h+1−0

@@ -1658,6 +1658,7 @@ extern void trace_event_enable_tgid_record(bool enable); · 1657 unmodified lines
1658	extern int event_trace_init(void);	1658	extern int event_trace_init(void);
1659	extern int event_trace_add_tracer(struct dentry parent, struct trace_array tr);	1659	extern int event_trace_add_tracer(struct dentry parent, struct trace_array tr);
1660	extern int event_trace_del_tracer(struct trace_array *tr);	1660	extern int event_trace_del_tracer(struct trace_array *tr);
		1661	extern void __trace_early_add_events(struct trace_array *tr);
1661		1662
1662	extern struct trace_event_file __find_event_file(struct trace_array tr,	1663	extern struct trace_event_file __find_event_file(struct trace_array tr,
1663	const char *system,	1664	const char *system,

kernel/trace/trace_events.c+16−14

 #endif /* CONFIG_DYNAMIC_FTRACE */
 /*
- * The top level array has already had its trace_event_file
+ * The top level array and trace arrays created by boot-time tracing
- * descriptors created in order to allow for early events to
+ * have already had its trace_event_file descriptors created in order
- * be recorded. This function is called after the tracefs has been
+ * to allow for early events to be recorded.
- * initialized, and we now have to create the files associated
+ * This function is called after the tracefs has been initialized,
- * to the events.
+ * and we now have to create the files associated to the events.
  */
-static __init void
+static void __trace_early_add_event_dirs(struct trace_array *tr)
-__trace_early_add_event_dirs(struct trace_array *tr)
 {
 	struct trace_event_file *file;
 	int ret;
 }
 /*
- * For early boot up, the top trace array requires to have
+ * For early boot up, the top trace array and the trace arrays created
- * a list of events that can be enabled. This must be done before
+ * by boot-time tracing require to have a list of events that can be
- * the filesystem is set up in order to allow events to be traced
+ * enabled. This must be done before the filesystem is set up in order
- * early.
+ * to allow events to be traced early.
  */
-static __init void
+void __trace_early_add_events(struct trace_array *tr)
-__trace_early_add_events(struct trace_array *tr)
 {
 	struct trace_event_call *call;
 	int ret;
 		goto out;
 	down_write(&trace_event_sem);
-	__trace_add_event_dirs(tr);
+	/* If tr already has the event list, it is initialized in early boot. */
+	if (unlikely(!list_empty(&tr->events)))
+		__trace_early_add_event_dirs(tr);
+	else
+		__trace_add_event_dirs(tr);
 	up_write(&trace_event_sem);
  out:

tracing/boot: Initialize per-instance event list in early boot

Keyboard shortcuts

General

Issues and pull requests

Issues, pull requests and Inbox

Repository code