From a838deab4e635994476bfc5b254bdf461e168752 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 10 Sep 2020 21:38:58 +0900 Subject: [PATCH] tracing: Enable adding dynamic events early stage Split the event fields initialization from creating new event directory. This allows the boot-time tracing to define dynamic events before initializing events directory on tracefs. Link: https://lkml.kernel.org/r/159974153790.478751.3475515065034825374.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 8e87fbab6930..42c0e7df6e70 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -38,6 +38,7 @@ DEFINE_MUTEX(event_mutex); LIST_HEAD(ftrace_events); static LIST_HEAD(ftrace_generic_fields); static LIST_HEAD(ftrace_common_fields); +static bool eventdir_initialized; #define GFP_TRACE (GFP_KERNEL | __GFP_ZERO) @@ -2486,7 +2487,10 @@ __trace_add_new_event(struct trace_event_call *call, struct trace_array *tr) if (!file) return -ENOMEM; - return event_create_dir(tr->event_dir, file); + if (eventdir_initialized) + return event_create_dir(tr->event_dir, file); + else + return event_define_fields(call); } /* @@ -3478,6 +3482,9 @@ __init int event_trace_init(void) if (ret) pr_warn("Failed to register trace events module notifier\n"); #endif + + eventdir_initialized = true; + return 0; }