On Fri, 10 Mar 2017 19:24:18 +0300 Gleb Fotengauer-Malinovskiy <[email protected]> wrote:
> The latest change of asm goto support check added passing of > KBUILD_CFLAGS to compiler. When these flags reference gcc plugins, > there is a race condition between the build of these plugins and their > use in this asm goto support check. > > 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. What exactly breaks when the race happens? -- Steve > > Reported-by: Anton V. Boyarshinov <[email protected]> > Fixes: 35f860f9ba6a ("jump label: pass kbuild_cflags when checking for asm > goto support") > Cc: [email protected] # v4.10 > Signed-off-by: Gleb Fotengauer-Malinovskiy <[email protected]> > Signed-off-by: Dmitry V. Levin <[email protected]> > --- > Makefile | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/Makefile b/Makefile > index 165cf97..7e3aade 100644 > --- a/Makefile > +++ b/Makefile > @@ -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 >
