objtool: Fix CONFIG_STACK_VALIDATION=y warning for out-of-tree modules

jpoimboe · Ingo Molnar · commit 9f0c18aec620 · 2017-02-20T09:49:34.000+01:00
When building a CONFIG_STACK_VALIDATION enabled kernel without the libelf devel package installed, the Makefile prints a warning: "Cannot use CONFIG_STACK_VALIDATION, please install libelf-dev, libelf-devel or elfutils-libelf-devel" But when building an out-of-tree module, the warning doesn't show. Instead it tries to use objtool, and the build fails with: /bin/sh: ./tools/objtool/objtool: No such file or directory Make sure the warning and the disabling of objtool occur in all cases, by moving the CONFIG_STACK_VALIDATION checks outside the 'ifeq ($(KBUILD_EXTMOD),)' block in the Makefile. Tested-By: Marc MERLIN <marc@merlins.org> Suggested-by: Jessica Yu <jeyu@redhat.com> Reported-by: Marc MERLIN <marc@merlins.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Jessica Yu <jeyu@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Marek <mmarek@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 3b27a0c ("objtool: Detect and warn if libelf is missing and don't break the build") Link: http://lkml.kernel.org/r/b3088ae4a8698143d4851965793c61fec2135b1f.1487182864.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/Makefile b/Makefile
@@ -908,6 +908,18 @@ mod_sign_cmd = true
 endif
 export mod_sign_cmd
 
+ifdef CONFIG_STACK_VALIDATION
+  has_libelf := $(call try-run,\
+		echo "int main() {}" | $(HOSTCC) -xc -o /dev/null -lelf -,1,0)
+  ifeq ($(has_libelf),1)
+    objtool_target := tools/objtool FORCE
+  else
+    $(warning "Cannot use CONFIG_STACK_VALIDATION, please install libelf-dev, libelf-devel or elfutils-libelf-devel")
+    SKIP_STACK_VALIDATION := 1
+    export SKIP_STACK_VALIDATION
+  endif
+endif
+
 
 ifeq ($(KBUILD_EXTMOD),)
 core-y		+= kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ block/
@@ -1035,18 +1047,6 @@ prepare0: archprepare gcc-plugins
 # All the preparing..
 prepare: prepare0 prepare-objtool
 
-ifdef CONFIG_STACK_VALIDATION
-  has_libelf := $(call try-run,\
-		echo "int main() {}" | $(HOSTCC) -xc -o /dev/null -lelf -,1,0)
-  ifeq ($(has_libelf),1)
-    objtool_target := tools/objtool FORCE
-  else
-    $(warning "Cannot use CONFIG_STACK_VALIDATION, please install libelf-dev, libelf-devel or elfutils-libelf-devel")
-    SKIP_STACK_VALIDATION := 1
-    export SKIP_STACK_VALIDATION
-  endif
-endif
-
 PHONY += prepare-objtool
 prepare-objtool: $(objtool_target)
 
