From: bot+bpf-ci@kernel.org
To: hui.zhu@linux.dev,ast@kernel.org,daniel@iogearbox.net,john.fastabend@gmail.com,andrii@kernel.org,eddyz87@gmail.com,memxor@gmail.com,martin.lau@linux.dev,song@kernel.org,yonghong.song@linux.dev,jolsa@kernel.org,emil@etsalapatis.com,ihor.solodrai@linux.dev,kpsingh@kernel.org,matt@bobrowski.net,rostedt@goodmis.org,mhiramat@kernel.org,mathieu.desnoyers@efficios.com,bpf@vger.kernel.org,linux-kernel@vger.kernel.org,linux-trace-kernel@vger.kernel.org
Cc: zhuhui@kylinos.cn,ast@kernel.org,andrii@kernel.org,daniel@iogearbox.net,martin.lau@kernel.org,eddyz87@gmail.com,yonghong.song@linux.dev,clm@meta.com,ihor.solodrai@linux.dev
Subject: Re: [PATCH v4] bpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure
Date: Mon, 10 Aug 2026 07:16:17 +0000 (UTC) [thread overview]
Message-ID: <f4de541e7b23a1990f50389f83010b2d70ff4d97a3cd408d18f89c5cd22492c9@mail.kernel.org> (raw)
In-Reply-To: <20260810061329.224276-1-hui.zhu@linux.dev>
[-- Attachment #1: Type: text/plain, Size: 2149 bytes --]
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index b4a10c9878cf..f4e8d372253a 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1518,8 +1518,8 @@ int arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_func
>
> int bpf_trampoline_multi_attach(struct bpf_prog *prog, u32 *ids,
> struct bpf_tracing_multi_link *link);
> -int bpf_trampoline_multi_detach(struct bpf_prog *prog,
> - struct bpf_tracing_multi_link *link);
> +void bpf_trampoline_multi_detach(struct bpf_prog *prog,
> + struct bpf_tracing_multi_link *link);
[ ... ]
> diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
> index e07af35ed040..90b70ea0d370 100644
> --- a/kernel/bpf/trampoline.c
> +++ b/kernel/bpf/trampoline.c
[ ... ]
> @@ -1756,7 +1766,8 @@ int bpf_trampoline_multi_attach(struct bpf_prog *prog, u32 *ids,
> return err;
> }
>
> -int bpf_trampoline_multi_detach(struct bpf_prog *prog, struct bpf_tracing_multi_link *link)
> +void bpf_trampoline_multi_detach(struct bpf_prog *prog,
> + struct bpf_tracing_multi_link *link)
[ ... ]
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 891897f8a1b3..29260951aa87 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -3687,7 +3687,7 @@ static void bpf_tracing_multi_link_release(struct bpf_link *link)
> struct bpf_tracing_multi_link *tr_link =
> container_of(link, struct bpf_tracing_multi_link, link);
>
> - WARN_ON_ONCE(bpf_trampoline_multi_detach(link->prog, tr_link));
> + bpf_trampoline_multi_detach(link->prog, tr_link);
> }
This isn't a bug, but would it be worth splitting the return-type
change into its own patch?
The int-to-void conversion of bpf_trampoline_multi_detach() touches
both bpf.h prototypes, the definition and the bpf_trace.c call site,
but is independent of the old_image lifetime fix that the Fixes: tag
refers to.
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/31362089875
prev parent reply other threads:[~2026-08-10 7:16 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-10 6:13 Hui Zhu
2026-08-10 7:16 ` bot+bpf-ci [this message]
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