diff --git a/CMakeLists.txt b/CMakeLists.txt
index faf61a839..094522f7f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,6 +5,9 @@ enable_language(ASM)
 
 set(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
 include(InstallSymlink)
+include(MacroEnsureOutOfSourceBuild)
+
+MACRO_ENSURE_OUT_OF_SOURCE_BUILD()
 
 set(DARLING_TOP_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}")
 set(DARLING_NO_EXECUTABLES OFF)
diff --git a/cmake/MacroEnsureOutOfSourceBuild.cmake b/cmake/MacroEnsureOutOfSourceBuild.cmake
new file mode 100644
index 000000000..c78281f28
--- /dev/null
+++ b/cmake/MacroEnsureOutOfSourceBuild.cmake
@@ -0,0 +1,14 @@
+macro( MACRO_ENSURE_OUT_OF_SOURCE_BUILD )
+string( COMPARE EQUAL "${CMAKE_SOURCE_DIR}" "${CMAKE_BINARY_DIR}" _insource )
+if( _insource )
+ message( FATAL_ERROR
+ "In-source builds are not allowed.
+ CMake would overwrite the Linux kernel module Makefile.
+ Please create a directory and run cmake from there, passing the path
+ to this source directory as the last argument.
+ This process created the file `CMakeCache.txt' and the directory `CMakeFiles'.
+ Please delete them."
+ )
+endif( _insource )
+endmacro( MACRO_ENSURE_OUT_OF_SOURCE_BUILD )
+
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 981413012..e04f42b2a 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -188,11 +188,6 @@ add_subdirectory(external/zsh)
 add_subdirectory(external/doc_cmds)
 add_subdirectory(external/libcxxabi)
 add_subdirectory(external/libcxx)
+add_subdirectory(lkm)
 
-#######################
-# Linux kernel module #
-#######################
 
-add_custom_target(lkm
-	COMMAND gmake
-	WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/lkm")
diff --git a/src/lkm b/src/lkm
index 5a5b433f1..00c2c8e39 160000
--- a/src/lkm
+++ b/src/lkm
@@ -1 +1 @@
-Subproject commit 5a5b433f109933a584328ba2c161906f4165be8a
+Subproject commit 00c2c8e39d2919736da09e0735d94eeb316929a5