Re: [PATCH bpf-next v8 2/8] selftests/bpf: Add basic libarena scaffolding

[sashiko-bot@kernel.org]

Sashiko AI review found 1 potential issue(s):
- [Low] Cross-compilation breakage for `test_libarena` due to missing target flags when using `$(CLANG)`.
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commit 8ad4036d8952c8f966e33882412f2b6f18aee582
Author: Emil Tsalapatis <emil@etsalapatis.com>

selftests/bpf: Add basic libarena scaffolding

This commit introduces an arena-based BPF library scaffolding, including a
test runner and Makefile. It sets up the standalone build for libarena and
adds temporary workarounds for bisectability.

> diff --git a/tools/testing/selftests/bpf/libarena/Makefile b/tools/testing/selftests/bpf/libarena/Makefile
> new file mode 100644
> index 0000000000000..304197e8a22f6
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/libarena/Makefile
[ ... ]
> +all: test_libarena
> +
> +test_libarena: selftest.c $(BPFOBJ) libarena.skel.h
> +	$(call msg,BINARY,libarena,$@)
> +	$(Q)$(CLANG) $(CFLAGS) $< $(BPFOBJ) $(LDLIBS) -o $@

Will this cause a cross-compilation breakage?

When cross-compiling, $(BPFOBJ) (libbpf.a) is built for the target
architecture using $(CC). Because $(CLANG) is used here without
target-specific flags (like --target=), selftest.c will be compiled
into a host-architecture object.

Attempting to link this host object with the target-architecture
libbpf.a will result in a linker error. Should user-space programs in
selftests be compiled using $(CC) to correctly target the cross-compilation
environment?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260421165037.4736-1-emil@etsalapatis.com?part=2