diff --git a/debian/changelog b/debian/changelog
index 5f1f70b2f..253f022a3 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -2,6 +2,7 @@ linux (4.4~rc5-1~exp2) UNRELEASED; urgency=medium
 
   * [sparc64] udeb: Replace mpt2sas with mpt3sas in scsi-common-modules
     (fixes FTBFS)
+  * mm: Fix missing #include in <linux/mmdebug.h> (fixes FTBFS on arm64)
 
  -- Ben Hutchings <ben@decadent.org.uk>  Thu, 17 Dec 2015 04:09:59 +0000
 
diff --git a/debian/patches/bugfix/all/mm-fix-missing-include-in-linux-mmdebug.h.patch b/debian/patches/bugfix/all/mm-fix-missing-include-in-linux-mmdebug.h.patch
new file mode 100644
index 000000000..2e7a2bcda
--- /dev/null
+++ b/debian/patches/bugfix/all/mm-fix-missing-include-in-linux-mmdebug.h.patch
@@ -0,0 +1,35 @@
+From: Ben Hutchings <ben@decadent.org.uk>
+Date: Sat, 19 Dec 2015 19:10:03 +0000
+Subject: mm: Fix missing #include in <linux/mmdebug.h>
+Forwarded: http://mid.gmane.org/20151219203034.GR28542@decadent.org.uk
+
+The various VM_WARN_ON/VM_BUG_ON macros depend on those defined by
+<linux/bug.h>.  Most users already include those, but not all; for
+example:
+
+  CC      arch/arm64/xen/../../arm/xen/grant-table.o
+In file included from arch/arm64/include/../../arm/include/asm/xen/page.h:5:0,
+                 from arch/arm64/include/asm/xen/page.h:1,
+                 from include/xen/page.h:28,
+                 from arch/arm64/xen/../../arm/xen/grant-table.c:33:
+arch/arm64/include/asm/pgtable.h: In function 'set_pte_at':
+arch/arm64/include/asm/pgtable.h:281:3: error: implicit declaration of function 'BUILD_BUG_ON_INVALID' [-Werror=implicit-function-declaration]
+   VM_WARN_ONCE(!pte_young(pte),
+
+Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
+---
+ include/linux/mmdebug.h | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
+index 877ef22..772362a 100644
+--- a/include/linux/mmdebug.h
++++ b/include/linux/mmdebug.h
+@@ -1,6 +1,7 @@
+ #ifndef LINUX_MM_DEBUG_H
+ #define LINUX_MM_DEBUG_H 1
+ 
++#include <linux/bug.h>
+ #include <linux/stringify.h>
+ 
+ struct page;
diff --git a/debian/patches/series b/debian/patches/series
index 41fada6d7..2b983d404 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -68,3 +68,4 @@ bugfix/all/usbvision-fix-overflow-of-interfaces-array.patch
 bugfix/all/media-usbvision-fix-crash-on-detecting-device-with-i.patch
 bugfix/x86/drm-i915-shut-up-gen8-sde-irq-dmesg-noise.patch
 bugfix/all/net-add-validation-for-the-socket-syscall-protocol.patch
+bugfix/all/mm-fix-missing-include-in-linux-mmdebug.h.patch