Patch "jump label: fix passing kbuild_cflags when checking for asm goto support" has been added to the 4.10-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
jump-label-fix-passing-kbuild_cflags-when-checking-for-asm-goto-support.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Gleb Fotengauer-Malinovskiy <[email protected]>
Date: Mon, 20 Mar 2017 20:15:53 +0300
Subject: jump label: fix passing kbuild_cflags when checking for asm goto support

From: Gleb Fotengauer-Malinovskiy <[email protected]>

commit 7292ae3d5a18fb922be496e6bb687647193569b4 upstream.

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.

---
 Makefile |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

@@ -651,6 +651,12 @@ KBUILD_CFLAGS += $(call cc-ifversion, -l
 # 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

@@ -796,12 +802,6 @@ KBUILD_CFLAGS   += $(call cc-option,-Wer
 # 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

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/jump-label-fix-passing-kbuild_cflags-when-checking-for-asm-goto-support.patch