From: Martin KaFai Lau <martin.lau@linux.dev>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>,
ameryhung@gmail.com, andrii@kernel.org, ast@kernel.org,
bpf@vger.kernel.org, daniel@iogearbox.net, eddyz87@gmail.com,
grbell@redhat.com, haoluo@google.com, john.fastabend@gmail.com,
jolsa@kernel.org, kpsingh@kernel.org, sdf@fomichev.me,
song@kernel.org, yonghong.song@linux.dev
Subject: Re: [PATCH] bpf: Release module BTF IDR before module unload
Date: Wed, 11 Mar 2026 12:55:03 -0700 [thread overview]
Message-ID: <2309925c-97dd-4298-bbe3-304a0d35670f@linux.dev> (raw)
In-Reply-To: <CAEf4BzaHWs1hhkhcFJRoza98R+zB8LnhSi4_00SXNgan+rAB0Q@mail.gmail.com>
On 3/11/26 12:17 PM, Andrii Nakryiko wrote:
>> For struct_ops prog, the module refcount is not held in prog->aux->mod.
>> I don't think it has to since it is not directly attached to the module.
>
> If we have something referencing a module, we should probably get and
> keep refcnt on it, no? Why would we have a pointer to a module we
> cannot be sure is still alive when we access it, sounds too
> error-prone to me.
>
>> For struct_ops map, it attaches the struct_ops prog to the module, so
>> the module refcount is held. It should be fine.
The module count is held but it is held by the struct_ops map. The
struct_ops prog doesn't use the module and doesn't have a pointer to a
module after it is loaded.
next prev parent reply other threads:[~2026-03-11 19:55 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-10 20:21 [PATCH bpf-next 0/1] Fix BPF struct_ops BTF cleanup race condition Gregory Bell
2026-03-10 20:21 ` [PATCH bpf-next 1/1] bpf: Fix BTF module cleanup race condition in struct_ops Gregory Bell
2026-03-10 20:58 ` bot+bpf-ci
2026-03-10 21:39 ` Kumar Kartikeya Dwivedi
2026-03-10 22:38 ` Amery Hung
2026-03-10 22:47 ` Kumar Kartikeya Dwivedi
2026-03-10 23:17 ` Amery Hung
2026-03-10 23:35 ` Kumar Kartikeya Dwivedi
2026-03-11 0:20 ` Martin KaFai Lau
2026-03-11 9:30 ` Kumar Kartikeya Dwivedi
2026-03-11 9:34 ` Kumar Kartikeya Dwivedi
2026-03-11 12:21 ` Alan Maguire
2026-03-11 13:05 ` Kumar Kartikeya Dwivedi
2026-03-11 13:03 ` [PATCH] bpf: Release module BTF IDR before module unload Kumar Kartikeya Dwivedi
2026-03-11 13:26 ` Kumar Kartikeya Dwivedi
2026-03-11 16:48 ` Greg Bell
2026-03-11 13:40 ` bot+bpf-ci
2026-03-11 19:10 ` Martin KaFai Lau
2026-03-11 19:17 ` Andrii Nakryiko
2026-03-11 19:55 ` Martin KaFai Lau [this message]
2026-03-12 3:08 ` kernel test robot
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