Hi,

I played a bit more with this.

I was irritated when I saw in my full make lines
-fstack-protector-strong and -fno-stack-protector simultaneously,
especially in x86/vdso.

First, I tried...

CC_STACKPROTECTOR_NONE n -> y
CC_STACKPROTECTOR_STRONG y -> n

This breaks at the same place in the same way (see attached file).

Then I tried to filter-out -fstack-protector-strong in the relevant
code parts with CC_STACKPROTECTOR_STRONG=y...

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index d998a487c9b1..5482e453a8ca 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -73,6 +73,7 @@ CFL := $(PROFILING) -mcmodel=small -fPIC -O2
-fasynchronous-unwind-tables -m64 \
        $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
        -fno-omit-frame-pointer -foptimize-sibling-calls \
        -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
+CFL += $(filter-out -fstack-protector-strong,$(KBUILD_CFLAGS))

 $(vobjs): KBUILD_CFLAGS := $(filter-out
$(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)

@@ -141,6 +142,7 @@ KBUILD_CFLAGS_32 := $(filter-out
-mcmodel=kernel,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out -fstack-protector-strong,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
 KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
 KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)

This breaks...

  if [ "" = "-pg" ]; then if [ arch/x86/entry/vdso/vgetcpu.o !=
"scripts/mod/empty.o" ]; then ./scripts/recordmcount
"arch/x86/entry/vdso/vgetcpu.o"; fi; fi;
  mycompiler -nostdlib -o arch/x86/entry/vdso/vdso64.so.dbg -fPIC
-shared -Wl,--hash-style=both -Wl,--build-id -Wl,-Bsymbolic  -m64
-Wl,-soname=linux-vdso.so.1 -Wl,--no-undefined
-Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096
-Wl,-T,arch/x86/entry/vdso/vdso.lds arch/x86/entry/vdso/vdso-note.o
arch/x86/entry/vdso/vclock_gettime.o arch/x86/entry/vdso/vgetcpu.o &&
sh ./arch/x86/entry/vdso/checkundef.sh 'nm'
'arch/x86/entry/vdso/vdso64.so.dbg'
/usr/bin/ld: arch/x86/entry/vdso/vclock_gettime.o: relocation
R_X86_64_32S against undefined hidden symbol `vvar_vsyscall_gtod_data'
can not be used when making a shared object
/usr/bin/ld: final link failed: Nonrepresentable section on output
clang: error: linker command failed with exit code 1 (use -v to see invocation)
  objcopy -S --localize-hidden  arch/x86/entry/vdso/vdso64.so.dbg
arch/x86/entry/vdso/vdso64.so
objcopy: 'arch/x86/entry/vdso/vdso64.so.dbg': No such file
arch/x86/entry/vdso/Makefile:124: recipe for target
'arch/x86/entry/vdso/vdso64.so' failed
make[6]: *** [arch/x86/entry/vdso/vdso64.so] Error 1

Cannot say stack-protector kconfig settings have an impact on this all.

Thanks.

Regards,
- Sedat -