From: Leon Hwang <leon.hwang@linux.dev>
To: Junseo Lim <zirajs7@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Jiri Olsa <jolsa@kernel.org>,
Emil Tsalapatis <emil@etsalapatis.com>,
bpf@vger.kernel.org, Sechang Lim <rhkrqnwk98@gmail.com>,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: Re: [PATCH bpf v2] bpf: keep trampoline progs alive until image release
Date: Thu, 20 Aug 2026 17:26:18 +0800 [thread overview]
Message-ID: <14c836d6-8919-40f8-8559-bd6048c14316@linux.dev> (raw)
In-Reply-To: <20260820022831.18601-1-zirajs7@gmail.com>
Hi Junseo,
On 20/8/26 10:28, Junseo Lim wrote:
> arch_prepare_bpf_trampoline() embeds program pointers in the generated
> image and passes them to __bpf_prog_enter_recur(). After
> bpf_trampoline_update() replaces the image, bpf_tramp_image_put() can keep
> the old image executable past a normal RCU grace period.
>
> A detached non-sleepable prog can therefore be freed before a preempted
> task reaches rcu_read_lock_dont_migrate() in __bpf_prog_enter_recur(),
> leading to a use-after-free.
>
> Keep image-local prog refs and drop them from bpf_tramp_image_free().
>
> Fixes: e21aa341785c ("bpf: Fix fexit trampoline.")
There was an existing fix [1]. Could you take a look at that fix?
[1]
https://lore.kernel.org/bpf/20260819122252.1782790-1-florent.revest@linux.dev/
Thanks,
Leon
> Reported-by: Sechang Lim <rhkrqnwk98@gmail.com>
> Signed-off-by: Junseo Lim <zirajs7@gmail.com>
> --- [...]
next prev parent reply other threads:[~2026-08-20 9:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-20 2:28 [PATCH bpf v2] bpf: keep trampoline progs alive until image release Junseo Lim
2026-08-20 2:42 ` sashiko-bot
2026-08-20 3:35 ` bot+bpf-ci
2026-08-20 9:26 ` Leon Hwang [this message]
2026-08-20 15:13 ` Junseo Lim
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=14c836d6-8919-40f8-8559-bd6048c14316@linux.dev \
--to=leon.hwang@linux.dev \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=eddyz87@gmail.com \
--cc=emil@etsalapatis.com \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=martin.lau@linux.dev \
--cc=memxor@gmail.com \
--cc=paulmck@kernel.org \
--cc=rhkrqnwk98@gmail.com \
--cc=song@kernel.org \
--cc=yonghong.song@linux.dev \
--cc=zirajs7@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox