Andrew Cooper suggested upgrading the orphan section warning to a hard link error. However Nathan Chancellor said outright turning the warning into an error with no escape hatch might be too aggressive, as we have had these warnings triggered by new compiler generated sections, and suggested turning orphan sections into an error only if CONFIG_WERROR is set. Kees Cook echoed and emphasized that the mandate from Linus is that we should avoid breaking builds. It wrecks bisection, it causes problems across compiler versions, etc. Thus upgrade the orphan section warning to a hard link error only if CONFIG_WERROR is set. Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Suggested-by: Nathan Chancellor <nathan@xxxxxxxxxx> Signed-off-by: Xin Li <xin3.li@xxxxxxxxx> Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx> --- Change since v1: * Introduce a new Kconfig item CONFIG_LD_ORPHAN_WARN_LEVEL to replace (if $(CONFIG_WERROR),error,warn) (Nathan Chancellor). --- Makefile | 2 +- arch/arm/boot/compressed/Makefile | 2 +- arch/arm64/kernel/vdso/Makefile | 2 +- arch/arm64/kernel/vdso32/Makefile | 2 +- arch/x86/boot/compressed/Makefile | 2 +- init/Kconfig | 15 ++++++++++++--- 6 files changed, 17 insertions(+), 8 deletions(-) diff --git a/Makefile b/Makefile index d148a55bfd0f..7c00bb1d562b 100644 --- a/Makefile +++ b/Makefile @@ -1118,7 +1118,7 @@ endif # We never want expected sections to be placed heuristically by the # linker. All sections should be explicitly named in the linker script. ifdef CONFIG_LD_ORPHAN_WARN -LDFLAGS_vmlinux += --orphan-handling=warn +LDFLAGS_vmlinux += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL) endif # Align the bit size of userspace programs with the kernel diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index 41bcbb460fac..53cadc3aaff1 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -123,7 +123,7 @@ LDFLAGS_vmlinux += --no-undefined LDFLAGS_vmlinux += -X # Report orphan sections ifdef CONFIG_LD_ORPHAN_WARN -LDFLAGS_vmlinux += --orphan-handling=warn +LDFLAGS_vmlinux += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL) endif # Next argument is a linker script LDFLAGS_vmlinux += -T diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 619e2dc7ee14..beaf9586338f 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -27,7 +27,7 @@ ldflags-y := -shared -soname=linux-vdso.so.1 --hash-style=sysv \ -Bsymbolic --build-id=sha1 -n $(btildflags-y) ifdef CONFIG_LD_ORPHAN_WARN - ldflags-y += --orphan-handling=warn + ldflags-y += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL) endif ldflags-y += -T diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index 36c8f66cad25..f59bd1a4ead6 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -104,7 +104,7 @@ VDSO_AFLAGS += -D__ASSEMBLY__ VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1 VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096 VDSO_LDFLAGS += -shared --hash-style=sysv --build-id=sha1 -VDSO_LDFLAGS += --orphan-handling=warn +VDSO_LDFLAGS += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL) # Borrow vdsomunge.c from the arm vDSO diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 3a261abb6d15..66b8a8cb5a0f 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -68,7 +68,7 @@ KBUILD_LDFLAGS += $(call ld-option,--no-ld-generated-unwind-info) # address by the bootloader. LDFLAGS_vmlinux := -pie $(call ld-option, --no-dynamic-linker) ifdef CONFIG_LD_ORPHAN_WARN -LDFLAGS_vmlinux += --orphan-handling=warn +LDFLAGS_vmlinux += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL) endif LDFLAGS_vmlinux += -z noexecstack ifeq ($(CONFIG_LD_IS_BFD),y) diff --git a/init/Kconfig b/init/Kconfig index abf65098f1b6..b416594d5689 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -159,10 +159,12 @@ config WERROR help A kernel build should not cause any compiler warnings, and this enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags - to enforce that rule by default. + to enforce that rule by default. Certain warnings from other tools + such as the linker may be upgraded to errors with this option as + well. - However, if you have a new (or very old) compiler with odd and - unusual warnings, or you have some architecture with problems, + However, if you have a new (or very old) compiler or linker with odd + and unusual warnings, or you have some architecture with problems, you may need to disable this config option in order to successfully build the kernel. @@ -1454,6 +1456,13 @@ config LD_ORPHAN_WARN def_bool y depends on ARCH_WANT_LD_ORPHAN_WARN depends on $(ld-option,--orphan-handling=warn) + depends on $(ld-option,--orphan-handling=error) + +config LD_ORPHAN_WARN_LEVEL + string + depends on LD_ORPHAN_WARN + default "error" if WERROR + default "warn" config SYSCTL bool -- 2.34.1
