Re: linux-next: build failure after merge of the bpf-next tree

[sashiko-bot@kernel.org]

Sashiko AI review found 1 potential issue(s):
- [Low] Incomplete adaptation to the btf_vlen() return type change.
--

commit 0212f8f14ef9fb92c19bf796baf0b7ea6478e094
Author: Thierry Reding <thierry.reding@kernel.org>

linux-next: build failure after merge of the bpf-next tree

After merging the bpf-next tree, today's linux-next build (x86_64_perf)
failed due to a sign-compare error. This patch fixes the build by changing
loop variables to match the unsigned return type of btf_vlen().

> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index e58c49d047a2..d22e20a57b70 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -969,7 +969,7 @@ static bool syscall_arg__strtoul_btf_enum(char *bf, size_t size, struct syscall_
>  	struct btf *btf = arg->trace->btf;
>  	struct btf_enum *be = btf_enum(bt);
>  
> -	for (int i = 0; i < btf_vlen(bt); ++i, ++be) {
> +	for (u32 i = 0; i < btf_vlen(bt); ++i, ++be) {
>  		const char *name = btf__name_by_offset(btf, be->name_off);
>  		int max_len = max(size, strlen(name));

Should btf_enum_scnprintf() in the same file also be updated for
consistency?

It appears the unsigned return value of btf_vlen() is implicitly cast to int
there, masking the sign-compare warning:

tools/perf/builtin-trace.c:btf_enum_scnprintf() {
    ...
	const int nr_entries = btf_vlen(type);

	for (int i = 0; i < nr_entries; ++i, ++be) {
    ...
}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260427132604.3754048-1-thierry.reding@kernel.org?part=1