diff -Nru lttng-modules-2.9.0/debian/changelog lttng-modules-2.9.0/debian/changelog
--- lttng-modules-2.9.0/debian/changelog	2017-06-26 13:53:11.000000000 +0000
+++ lttng-modules-2.9.0/debian/changelog	2017-07-17 10:57:59.000000000 +0000
@@ -1,3 +1,10 @@
+lttng-modules (2.9.0-1ubuntu3) artful; urgency=medium
+
+  * Fix missing ftrace headers on v4.11 (LP: #1704720)
+    - adjust a previous kernel version check from v4.12 to v4.11
+
+ -- Colin Ian King <colin.king@canonical.com>  Mon, 17 Jul 2017 11:57:59 +0100
+
 lttng-modules (2.9.0-1ubuntu2) artful; urgency=medium
 
   * Cherry picks to fix build isues with 4.11 and 4.12 (LP: #1699755)
diff -Nru lttng-modules-2.9.0/debian/patches/0023-Fix-missing-ftrace-header-on-v4.11.patch lttng-modules-2.9.0/debian/patches/0023-Fix-missing-ftrace-header-on-v4.11.patch
--- lttng-modules-2.9.0/debian/patches/0023-Fix-missing-ftrace-header-on-v4.11.patch	1970-01-01 00:00:00.000000000 +0000
+++ lttng-modules-2.9.0/debian/patches/0023-Fix-missing-ftrace-header-on-v4.11.patch	2017-07-17 10:56:14.000000000 +0000
@@ -0,0 +1,30 @@
+Subject: Fix: handle missing ftrace header on v4.11
+
+Properly handle the case where we build against the distro headers of a
+kernel >= 4.11 and ftrace is enabled but the private header is
+unavailable.
+
+Signed-off-by: Colin Ian King <colin.king@canonical.com>
+
+Index: lttng-modules-2.9.0/Makefile.ABI.workarounds
+===================================================================
+--- lttng-modules-2.9.0.orig/Makefile.ABI.workarounds
++++ lttng-modules-2.9.0/Makefile.ABI.workarounds
+@@ -22,7 +22,7 @@ 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
++# Starting with kernel 4.11, 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.
+@@ -30,7 +30,7 @@ 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 [ $(VERSION) -ge 5 -o \( $(VERSION) -eq 4 -a $(PATCHLEVEL) -ge 11 \) ] ; then \
+       if [ -z "$(ftrace_dep_check)" ] ; then \
+         echo "no" ; \
+         exit ; \
diff -Nru lttng-modules-2.9.0/debian/patches/series lttng-modules-2.9.0/debian/patches/series
--- lttng-modules-2.9.0/debian/patches/series	2017-06-26 12:32:11.000000000 +0000
+++ lttng-modules-2.9.0/debian/patches/series	2017-07-17 10:53:44.000000000 +0000
@@ -20,3 +20,4 @@
 0020-Fix-Build-ftrace-probe-on-kernels-prior-to-4.12.patch
 0021-Fix-handle-missing-ftrace-header-on-v4.12.patch
 0022-Fix-section-mismatch-warning-caused-by-__exit-annota.patch
+0023-Fix-missing-ftrace-header-on-v4.11.patch