Re: [PATCH bpf-next v8 7/8] selftests/bpf: Add selftests for libarena buddy allocator

[sashiko-bot@kernel.org]

Sashiko AI review found 1 potential issue(s):
- [Low] Using the `%lx` format specifier for a pointer type without a cast causes a compiler warning in BPF selftests.
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commit 5722468489c153ff642e633e17b799603b516db1
Author: Emil Tsalapatis <emil@etsalapatis.com>

selftests/bpf: Add selftests for libarena buddy allocator
    
Introduce selftests for the buddy allocator with and without ASAN. Add the
libarena selftests both to the libarena test runner and to test_progs,
and add logic in the Makefile to only compile the ASAN variant if the
compiler supports it.

> diff --git a/tools/testing/selftests/bpf/libarena/selftests/st_buddy.bpf.c b/tools/testing/selftests/bpf/libarena/selftests/st_buddy.bpf.c
> new file mode 100644
> index 0000000000000..b12d18790fa53
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/libarena/selftests/st_buddy.bpf.c
[ ... ]
> +SEC("syscall")
> +__weak int test_buddy_alloc_multiple(void)
> +{
[ ... ]
> +	for (i = 10; i < SEGARRLEN && can_loop; i++) {
> +		idx = (i * 17) % SEGARRLEN;
> +
> +		mem = segarr[idx].block;
> +		sz = segarr[idx].sz;
> +		poison = segarr[idx].poison;
> +
> +		for (j = zero; j < sz && can_loop; j++) {
> +			if (mem[j] != poison) {
> +				buddy_destroy(&buddy);
> +				arena_stdout("%s:%d %lx %u vs %u", __func__,
> +					   __LINE__, &mem[j], mem[j], poison);

Does passing a pointer to the %lx format specifier cause a compiler warning
here?

Since &mem[j] is a pointer type (u8 __arena *), passing it to %lx without a
cast usually triggers a format warning. Because BPF selftests are compiled
with -Werror, this can break the build.

Should it be cast to an integer type like (unsigned long), similar to how
it is handled later on in test_buddy_alignment()?

> +				return -EINVAL;
> +			}
> +		}
> +
> +		buddy_free(&buddy, mem);
> +	}
> +
> +	buddy_destroy(&buddy);
> +
> +	return 0;
> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260421165037.4736-1-emil@etsalapatis.com?part=7