Commit 9f0c18ae authored Feb 15, 2017 by Josh Poimboeuf Committed by Ingo Molnar Feb 20, 2017

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



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: 3b27a0c8 ("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>

parent c470abd4

Makefile

+12 −12

Original line number	Diff line number	Diff line
		@@ -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)

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