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

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Message-Id: <DBR2SLKGO5OO.276GT83Y3D6DA@pwned.life>
Date: Fri, 01 Aug 2025 14:04:54 +0200
From: "Achill Gilgenast" <fossdd@...ed.life>
To: "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@...r.kernel.org>
Cc: <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>, "Achill Gilgenast" <fossdd@...ed.life>
Subject: Re: [PATCH] libbpf: avoid possible use of uninitialized mod_len

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
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