From ff4d1d7e85be94ef43709cd698f0ec9a12f247d1 Mon Sep 17 00:00:00 2001
From: Beniamin Sandu <beniaminsandu@gmail.com>
Date: Thu, 13 Aug 2020 16:24:39 +0300
Subject: [PATCH 01/10] Kconfig: fix dependency issue when building in-tree
 without CONFIG_FTRACE

When building in-tree, one could disable CONFIG_FTRACE from kernel
config which will leave CONFIG_TRACEPOINTS selected by LTTNG modules,
but generate a lot of linker errors like below because it leaves out
other stuff, e.g.:

trace.c:(.text+0xd86b): undefined reference to `trace_event_buffer_reserve'
ld: trace.c:(.text+0xd8de): undefined reference to `trace_event_buffer_commit'
ld: trace.c:(.text+0xd926): undefined reference to `event_triggers_call'
ld: trace.c:(.text+0xd942): undefined reference to `trace_event_ignore_this_pid'
ld: net/mac80211/trace.o: in function `trace_event_raw_event_drv_tdls_cancel_channel_switch':

It appears to be caused by the fact that TRACE_EVENT macros in the Linux
kernel depend on the Ftrace ring buffer as soon as CONFIG_TRACEPOINTS is
enabled.

Steps to reproduce:

- Get a clone of an upstream stable kernel and use scripts/built-in.sh on it

- Configure a standard x86-64 build, enable built-in LTTNG but disable
  CONFIG_FTRACE from Kernel Hacking-->Tracers using menuconfig

- Build will fail at linking stage

Upstream-Status: Backport

Signed-off-by: Beniamin Sandu <beniaminsandu@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
 Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Kconfig b/Kconfig
index acdab73..10eccff 100644
--- a/Kconfig
+++ b/Kconfig
@@ -2,7 +2,7 @@
 
 config LTTNG
 	tristate "LTTng support"
-	select TRACEPOINTS
+	select TRACING
 	help
 	  LTTng is an open source tracing framework for Linux.
 
-- 
2.19.1