Re: [PATCH v3 4/5] tools/build: selftests: Allow versioning LLVM lld

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] Bypassing Clang's internal linker path resolution causes silent linker version mismatches for out-of-path toolchains.
- [Low] Unbalanced parenthesis in the `USE_LD_ERR` error messages.
--

--- Patch [4]: [PATCH v3 4/5] tools/build: selftests: Allow versioning LLVM lld ---
commit cdccb2d14502b0641ebfd4e8ddb945bdb605ed46
Author: James Clark <james.clark@linaro.org>

tools/build: selftests: Allow versioning LLVM lld

This commit updates the BPF selftests Makefile to use the LLD variable
from Makefile.include to ensure consistency with the rest of the LLVM
toolchain. It explicitly resolves paths to the linker via shell commands
and passes the result to clang's -fuse-ld flag.

> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -264,30 +264,34 @@ $(OUTPUT)/%:%.c
>  
>  # LLVM's ld.lld doesn't support all the architectures, so use it only on x86
>  ifeq ($(SRCARCH),$(filter $(SRCARCH),x86 riscv))
> -LLD := lld
> +USE_LD := $(shell command -v $(LLD))

[Severity: Medium]
Will this shell resolution cause silent linker version mismatches if a user
builds with an out-of-path compiler (e.g., CLANG=/path/to/clang) without
setting LLVM= or modifying the system PATH?

Previously, passing -fuse-ld=lld allowed clang to natively resolve the ld.lld
binary relative to its own executable path. Bypassing clang's internal linker
path resolution with `shell command -v` might cause the build to pick up a
system linker (like /usr/bin/ld.lld) instead of the bundled one.

> +USE_LD_ERR = linker '$(LLD)' not found - add it to PATH, or pass LLVM=/path/ or LLD=/abs/ld.lld)

[Severity: Low]
Is there an extra closing parenthesis at the end of this error message string?

>  else
> -LLD := $(shell command -v $(LD))
> +USE_LD := $(shell command -v $(LD))
> +USE_LD_ERR = linker '$(LD)' not found - add it to PATH, or pass LLVM=/path/ or LD=/abs/ld)

[Severity: Low]
Is there also an unbalanced closing parenthesis here?

>  endif

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260715-james-perf-llvm-version-v3-0-8854bfe5af7e@linaro.org?part=4