[Buildroot] [PATCH v2, 1/1] package/kvm-unit-tests: fix build without ssp on x86_64

[Yann E. MORIN <yann.morin.1998@free.fr>]

Arnout, All,

On 2019-05-26 20:20 +0200, Arnout Vandecappelle spake thusly:
> On 26/05/2019 00:22, Fabrice Fontaine wrote:
> > Makefile tries to detect stack-protector which will result in build
> > failure on x86_64 if ssp is not available on host compiler so disable
> > stack protector through EXTRA_CFLAGS
> 
>  I would like to actually understand the failure though... The error is:
> 
> /usr/bin/ld: x86/realmode.o: in function `print_serial_u32':
> .../x86/realmode.c:104: undefined reference to `__stack_chk_fail'
> 
>  However, realmode.c is built with
> 
> gcc  -mno-red-zone -m32 -O1 -g -MMD -MF x86/.realmode.d  -Wall -Wwrite-strings
> -Wclobbered -Wempty-body -Wuninitialized -Wignored-qualifiers
> -Wunused-but-set-parameter  -fno-omit-frame-pointer    -Wno-frame-address
> -fno-pic  -no-pie -Wmissing-parameter-type -Wold-style-declaration
> -Woverride-init -std=gnu99 -ffreestanding -I
> /data/buildroot/buildroot-test/instance-1/output/build/kvm-unit-tests-kvm-unit-tests-20171020/lib
> -I
> /data/buildroot/buildroot-test/instance-1/output/build/kvm-unit-tests-kvm-unit-tests-20171020/lib/x86
> -I lib   -c -o x86/realmode.o x86/realmode.c
> 
>  So, stack-protector is *not* enabled... So what the hell is going on here?
> 
>  It seems to only happen on Xogium's Arch Linux server. Maybe there's something
> weird going on with that server?

That's because:

  - kvm-unit-tests, on x86_64 target, uses the host compiler to build:
    https://git.buildroot.org/buildroot/tree/package/kvm-unit-tests/kvm-unit-tests.mk#n34

  - Xogium's autobuilder is running Arch Linux, which enables SSP by
    default, yes.

Regards,
Yann E. MORIN.

>  Regards,
>  Arnout
> 
> > 
> > Fixes:
> >  - http://autobuild.buildroot.org/results/e6f767755ffdb5ecc014eb5ad7519814f075a60e
> > 
> > Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
> > ---
> > Changes v1 -> v2 (after review of Peter Korsgaard):
> >  - Always disable stack-protector on x86_64 as we're using host compiler
> > 
> >  package/kvm-unit-tests/kvm-unit-tests.mk | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> > 
> > diff --git a/package/kvm-unit-tests/kvm-unit-tests.mk b/package/kvm-unit-tests/kvm-unit-tests.mk
> > index 92d67fb34b..72762d21f2 100644
> > --- a/package/kvm-unit-tests/kvm-unit-tests.mk
> > +++ b/package/kvm-unit-tests/kvm-unit-tests.mk
> > @@ -37,6 +37,8 @@ KVM_UNIT_TESTS_CONF_OPTS =\
> >  # x86-64 cannot do.
> >  ifneq ($(BR2_x86_64),y)
> >  KVM_UNIT_TESTS_CONF_OPTS += --cross-prefix="$(TARGET_CROSS)"
> > +# Don't force -fstack-protector as we don't know if host compiler supports ssp 
> > +KVM_UNIT_TESTS_MAKE_OPTS += EXTRA_CFLAGS=-fno-stack-protector
> >  endif
> >  
> >  define KVM_UNIT_TESTS_CONFIGURE_CMDS
> > @@ -44,11 +46,12 @@ define KVM_UNIT_TESTS_CONFIGURE_CMDS
> >  endef
> >  
> >  define KVM_UNIT_TESTS_BUILD_CMDS
> > -	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) standalone
> > +	$(TARGET_MAKE_ENV) $(MAKE) $(KVM_UNIT_TESTS_MAKE_OPTS) -C $(@D) \
> > +		standalone
> >  endef
> >  
> >  define KVM_UNIT_TESTS_INSTALL_TARGET_CMDS
> > -	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) \
> > +	$(TARGET_MAKE_ENV) $(MAKE) $(KVM_UNIT_TESTS_MAKE_OPTS) -C $(@D) \
> >  		DESTDIR=$(TARGET_DIR)/usr/share/kvm-unit-tests/ \
> >  		install
> >  endef
> > 
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