The top level Makefile explicitly sets the C standard used in the kernel to gnu89. By overriding KBUILD_CFLAGS, the C standard used for this subdir is now implicit based on compiler and compiler version. GCC changes this implicit default from gnu89 to gnu11 in v5.1.
This implies that depending on compiler version, parts of the kernel are being linked together from object files that were compiled with different C standard compiler flags. This is problematic for symbols declared as extern inline, as the semantics have switched since gnu89. See also: http://blahg.josefsipek.net/?p=529 Signed-off-by: Nick Desaulniers <ndesaulni...@google.com> Tested-by: Sedat Dilek <sedat.di...@gmail.com> --- arch/x86/boot/compressed/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index fa42f895fdde..1a04c7e9add1 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -26,7 +26,7 @@ KCOV_INSTRUMENT := n targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \ vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4 -KBUILD_CFLAGS := -m$(BITS) -O2 +KBUILD_CFLAGS := -m$(BITS) -O2 -std=gnu89 KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC) KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING cflags-$(CONFIG_X86_32) := -march=i386 -- 2.17.0.921.gf22659ad46-goog -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
