Commit 7292ae3d authored Mar 20, 2017 by Gleb Fotengauer-Malinovskiy Committed by Masahiro Yamada Mar 22, 2017

jump label: fix passing kbuild_cflags when checking for asm goto support



The latest change of asm goto support check added passing of KBUILD_CFLAGS
to compiler.  When these flags reference gcc plugins that are not built yet,
the check fails.

When one runs "make bzImage" followed by "make modules", the kernel is always
built with HAVE_JUMP_LABEL disabled, while the modules are built depending on
CONFIG_JUMP_LABEL.  If HAVE_JUMP_LABEL macro happens to be different, modules
are built with undefined references, e.g.:

ERROR: "static_key_slow_inc" [net/netfilter/xt_TEE.ko] undefined!
ERROR: "static_key_slow_dec" [net/netfilter/xt_TEE.ko] undefined!
ERROR: "static_key_slow_dec" [net/netfilter/nft_meta.ko] undefined!
ERROR: "static_key_slow_inc" [net/netfilter/nft_meta.ko] undefined!
ERROR: "nf_hooks_needed" [net/netfilter/ipvs/ip_vs.ko] undefined!
ERROR: "nf_hooks_needed" [net/ipv6/ipv6.ko] undefined!
ERROR: "static_key_count" [net/ipv6/ipv6.ko] undefined!
ERROR: "static_key_slow_inc" [net/ipv6/ipv6.ko] undefined!

This change moves the check before all these references are added
to KBUILD_CFLAGS.  This is correct because subsequent KBUILD_CFLAGS
modifications are not relevant to this check.

Reported-by: Anton V. Boyarshinov <boyarsh@altlinux.org>
Fixes: 35f860f9 ("jump label: pass kbuild_cflags when checking for asm goto support")
Cc: stable@vger.kernel.org	# v4.10
Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: David Lin <dtwlin@google.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

parent b334e19a

Makefile

+6 −6

Original line number	Diff line number	Diff line
		@@ -653,6 +653,12 @@ KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \
		# Tell gcc to never replace conditional load with a non-conditional one
		KBUILD_CFLAGS += $(call cc-option,--param=allow-store-data-races=0)

		# check for 'asm goto'
		ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
		KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
		KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
		endif

		include scripts/Makefile.gcc-plugins

		ifdef CONFIG_READABLE_ASM
		@@ -798,12 +804,6 @@ KBUILD_CFLAGS += $(call cc-option,-Werror=incompatible-pointer-types)
		# use the deterministic mode of AR if available
		KBUILD_ARFLAGS := $(call ar-option,D)

		# check for 'asm goto'
		ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
		KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
		KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
		endif

		include scripts/Makefile.kasan
		include scripts/Makefile.extrawarn
		include scripts/Makefile.ubsan