linux-kernel - Re: [PATCH] libbpf: avoid possible use of uninitialized mod

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Message-ID: <CAADnVQKfTgPmuOcGHsQyLdCeVi9hucyQVkfZLeAxDrSbc8_Xmg@mail.gmail.com>
Date: Fri, 1 Aug 2025 08:16:48 -0700
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: Achill Gilgenast <fossdd@...ed.life>
Cc: Eduard Zingerman <eddyz87@...il.com>, Yonghong Song <yonghong.song@...ux.dev>, 
	Alexei Starovoitov <ast@...nel.org>, Daniel Borkmann <daniel@...earbox.net>, 
	Andrii Nakryiko <andrii@...nel.org>, Viktor Malik <vmalik@...hat.com>, bpf <bpf@...r.kernel.org>, 
	LKML <linux-kernel@...r.kernel.org>, Martin KaFai Lau <martin.lau@...ux.dev>, 
	Song Liu <song@...nel.org>, John Fastabend <john.fastabend@...il.com>, 
	KP Singh <kpsingh@...nel.org>, Stanislav Fomichev <sdf@...ichev.me>, Hao Luo <haoluo@...gle.com>, 
	Jiri Olsa <jolsa@...nel.org>
Subject: Re: [PATCH] libbpf: avoid possible use of uninitialized mod_len

On Fri, Aug 1, 2025 at 5:05 AM Achill Gilgenast <fossdd@...ed.life> wrote:
>
> On Fri Aug 1, 2025 at 1:46 PM CEST, Achill Gilgenast wrote:
> > If not fn_name, mod_len does never get initialized which fails now with
> > gcc15 on Alpine Linux edge:
> >
> >       libbpf.c: In function 'find_kernel_btf_id.constprop':
> >       libbpf.c:10100:33: error: 'mod_len' may be used uninitialized [-Werror=maybe-uninitialized]
> >       10100 |                 if (mod_name && strncmp(mod->name, mod_name, mod_len) != 0)
> >             |                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >       libbpf.c:10070:21: note: 'mod_len' was declared here
> >       10070 |         int ret, i, mod_len;
> >             |                     ^~~~~~~
> >
> > Signed-off-by: Achill Gilgenast <fossdd@...ed.life>
> > Acked-by: Yonghong Song <yonghong.song@...ux.dev>
> > Acked-by: Eduard Zingerman <eddyz87@...il.com>
> > Link: https://lore.kernel.org/bpf/20250729094611.2065713-1-fossdd@pwned.life/
>
> Oops, the subject should've been v2. I forgot to pass -v2 to git
> send-email.

No. It was already applied.