Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] ld-option incorrectly evaluates to true for -z force-bti on older GNU ld versions, causing build failures.
--
--- Patch [11]: [PATCH 11/12] arm64/bti: Force-enable BTI linker veneers ---
commit dc92fd3fe21010a76154b8b30a8e4ff7c0d55416
Author: Josh Poimboeuf <[email protected]>
arm64/bti: Force-enable BTI linker veneers
This commit force-enables BTI veneers using the "-z force-bti" linker
option to ensure they are created even if some input objects are missing
the BTI feature bit. This aims to prevent silent runtime BTI exceptions
on larger kernels.
> diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> index 4eee721c0b278..d0db9a6766a2f 100644
> --- a/arch/arm64/Makefile
> +++ b/arch/arm64/Makefile
> @@ -25,6 +25,7 @@ endif
>
> ifeq ($(CONFIG_ARM64_BTI_KERNEL),y)
> KBUILD_AFLAGS += -include $(srctree)/arch/arm64/include/asm/bti-note.h
> +LDFLAGS_vmlinux += $(call ld-option,-z force-bti)
[Severity: Medium]
Does this ld-option check reliably detect if the linker supports "-z force-bti"?
When Kbuild's ld-option tests linker support, it executes the linker with "-v".
However, when GNU ld is invoked with "-v" and no input files, it prints its
version information and immediately exits with a 0 status code, completely
bypassing any validation of keyword arguments like "-z".
Because of this, ld-option will falsely report that "-z force-bti" is supported
on all versions of GNU ld, even older versions (prior to 2.34) where the option
was not yet introduced.
During the actual kernel link, ld parses the "-z" list, fails to recognize
"force-bti", and emits an ignored warning. If CONFIG_WERROR=y is set, the linker
escalates this warning to a fatal error and breaks the build. On builds without
CONFIG_WERROR, the warning is ignored and the patch silently fails to enforce
the intended BTI veneers.
> endif
>
> cc_has_k_constraint := $(call try-run,echo \
--
Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=11
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