[LTP] [RFC PATCH] kvm: Fix Nix build failure by specifying -fno-stack-protector again

[Richard Palethorpe]

Nix uses a binutils wrapper of some sort to allow switching between
toolchains. This seems to be causing a problem for the KVM tests
although it may not be unique to Nix.

gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -DCOMPILE_PAYLOAD -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx\
 -mno-sse -fno-pie -c -o lib_guest.o lib_guest.c
as  -c -o bootstrap_x86_64.o bootstrap_x86_64.S
gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -DCOMPILE_PAYLOAD -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx\
 -mno-sse -fno-pie -c -o lib_x86.o lib_x86.c
gcc -I/home/rich/kernel/ltp/testcases/kernel/kvm/include -I../../../include -I../../../include -I../../../include/old/ -DCOMPILE_PAYLOAD -ff\
reestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx -mno-sse -fno-pie -nostdlib -Wl,--build-id=none -fno-stack-protector -z noexe\
cstack -no-pie -Wl,-T/home/rich/kernel/ltp/testcases/kernel/kvm/linker/x86_64.lds -o kvm_pagefault01-payload.elf kvm_pagefault01.c lib_guest\
.o bootstrap_x86_64.o lib_x86.o
/nix/store/inq79dwl8sz1ygmfbgsmg77i5cwmdjpz-binutils-2.40/bin/ld: lib_x86.o: in function `kvm_init_guest_vmcb':
lib_x86.c:(.text+0x7b3): undefined reference to `__stack_chk_fail'
collect2: error: ld returned 1 exit status
make: *** [Makefile:58: kvm_pagefault01-payload.o] Error 1

IIUC __stack_chk_fail is added to lib_x86.o which means that
-fstack-protector somehow gets added to the compilation of lib_x86.o.

I found that adding the GUEST_LDFLAGS to the lib_*.o compilations
fixes the issue on Nix.
---
 testcases/kernel/kvm/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/testcases/kernel/kvm/Makefile b/testcases/kernel/kvm/Makefile
index d9eb10728..ddb24fabe 100644
--- a/testcases/kernel/kvm/Makefile
+++ b/testcases/kernel/kvm/Makefile
@@ -46,7 +46,7 @@ MAKE_TARGETS =
 endif
 
 lib_guest.o $(ARCH_OBJ): CPPFLAGS	:= $(GUEST_CPPFLAGS)
-lib_guest.o $(ARCH_OBJ): CFLAGS		:= $(GUEST_CFLAGS)
+lib_guest.o $(ARCH_OBJ): CFLAGS		:= $(GUEST_CFLAGS) $(GUEST_LDFLAGS)
 
 kvm_svm03: CFLAGS += -pthread
 kvm_svm03: LDLIBS += -pthread
-- 
2.40.1