From f61d99f9c276bc659f8789a15de19e00f2e3bc12 Mon Sep 17 00:00:00 2001 From: Michael Jeanson Date: Fri, 23 Jun 2017 14:29:42 -0400 Subject: [PATCH] Fix: handle missing ftrace header on v4.12 Properly handle the case where we build against the distro headers of a kernel >= 4.12 and ftrace is enabled but the private header is unavailable. Signed-off-by: Michael Jeanson Signed-off-by: Mathieu Desnoyers --- Makefile.ABI.workarounds | 21 +++++++++++++++++++++ lttng-events.h | 2 +- probes/Kbuild | 19 ++++--------------- 3 files changed, 26 insertions(+), 16 deletions(-) diff --git a/Makefile.ABI.workarounds b/Makefile.ABI.workarounds index c3717f81..2e6c4aa2 100644 --- a/Makefile.ABI.workarounds +++ b/Makefile.ABI.workarounds @@ -27,3 +27,24 @@ RT_PATCH_VERSION:=$(shell $(TOP_LTTNG_MODULES_DIR)/rt-patch-version.sh $(CURDIR) ifneq ($(RT_PATCH_VERSION), 0) ccflags-y += -DRT_PATCH_VERSION=$(RT_PATCH_VERSION) endif + +# Starting with kernel 4.12, the ftrace header was moved to private headers +# and as such is not available when building against distro headers instead +# of the full kernel sources. In the situation, define LTTNG_FTRACE_MISSING_HEADER +# so we can enable the compat code even if CONFIG_DYNAMIC_FTRACE is enabled. +ifneq ($(CONFIG_DYNAMIC_FTRACE),) + ftrace_dep = $(srctree)/kernel/trace/trace.h + ftrace_dep_check = $(wildcard $(ftrace_dep)) + have_ftrace_header = $(shell \ + if [ $(VERSION) -ge 5 -o \( $(VERSION) -eq 4 -a $(PATCHLEVEL) -ge 12 \) ] ; then \ + if [ -z "$(ftrace_dep_check)" ] ; then \ + echo "no" ; \ + exit ; \ + fi; \ + fi; \ + echo "yes" ; \ + ) + ifeq ($(have_ftrace_header), no) + ccflags-y += -DLTTNG_FTRACE_MISSING_HEADER + endif +endif diff --git a/lttng-events.h b/lttng-events.h index f55bf663..17dd8d3a 100644 --- a/lttng-events.h +++ b/lttng-events.h @@ -810,7 +810,7 @@ int lttng_kretprobes_event_enable_state(struct lttng_event *event, } #endif -#ifdef CONFIG_DYNAMIC_FTRACE +#if defined(CONFIG_DYNAMIC_FTRACE) && !defined(LTTNG_FTRACE_MISSING_HEADER) int lttng_ftrace_register(const char *name, const char *symbol_name, struct lttng_event *event); diff --git a/probes/Kbuild b/probes/Kbuild index 78bf3fb2..cc1c0656 100644 --- a/probes/Kbuild +++ b/probes/Kbuild @@ -259,22 +259,11 @@ ifneq ($(CONFIG_KRETPROBES),) endif # CONFIG_KRETPROBES ifneq ($(CONFIG_DYNAMIC_FTRACE),) - ftrace_dep = $(srctree)/kernel/trace/trace.h - ftrace_dep_check = $(wildcard $(ftrace_dep)) - ftrace = $(shell \ - if [ $(VERSION) -ge 5 -o \( $(VERSION) -eq 4 -a $(PATCHLEVEL) -ge 12 \) ] ; then \ - if [ -z "$(ftrace_dep_check)" ] ; then \ - echo "warn" ; \ - exit ; \ - fi; \ - fi; \ - echo "lttng-ftrace.o" ; \ - ) - ifeq ($(ftrace),warn) + ifeq ($(have_ftrace_header),yes) + obj-$(CONFIG_LTTNG) += lttng-ftrace.o + else $(warning Files $(ftrace_dep) not found. Probe "ftrace" is disabled. Use full kernel source tree to enable it.) - ftrace = - endif # $(ftrace),warn - obj-$(CONFIG_LTTNG) += $(ftrace) + endif endif # CONFIG_DYNAMIC_FTRACE # vim:syntax=make -- 2.34.1