From: Jakub Kicinski <kuba@kernel.org>
To: Leon Hwang <leon.hwang@linux.dev>
Cc: bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Shuah Khan <shuah@kernel.org>,
"David S . Miller" <davem@davemloft.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Toke Hoiland-Jorgensen <toke@redhat.com>,
Lorenzo Bianconi <lorenzo@kernel.org>,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
netdev@vger.kernel.org, kernel-patches-bot@fb.com
Subject: Re: [PATCH bpf-next 1/3] bpf: Disallow freplace on XDP with mismatched xdp_has_frags values
Date: Fri, 27 Mar 2026 17:12:20 -0700 [thread overview]
Message-ID: <20260327171220.6d10d710@kernel.org> (raw)
In-Reply-To: <785e0b04-91e4-457f-8d6c-e0a911c0fd88@linux.dev>
On Fri, 27 Mar 2026 14:42:19 +0800 Leon Hwang wrote:
> > It may be worth adding a selftest to
> > tools/testing/selftests/drivers/net/xdp.py
> > which sets MTU to 9k, tries to attach a non-frag-capable prog
> > if that fails attaches a frag-capable prog and then checks if
> > replacing the capable prog with non-capable fails.
> > Drivers may be buggy in this regard.
>
> Do you mean adding these two tests to xdp.py?
>
> 1. Verify the failure of attaching non-frag-capable prog to mtu=9k
> driver.
> 2. Verify the failure of updating frag-capable prog with non-frag-
> capable prog via libbpf.c::bpf_link__update_program().
Not directly via libbpf just ip -f link, it uses libbpf internally
but testing with ip link is simpler. Also - there are already XDP
progs which return XDP_PASS in frag-capable and non-capable mode,
so just use those.
> As for test #2, it may require a helper to attach prog then update prog
> using libbpf's APIs.
See above.
next prev parent reply other threads:[~2026-03-28 0:12 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-24 15:04 [PATCH bpf-next 0/3] bpf: Enhance freplace compatibility Leon Hwang
2026-03-24 15:04 ` [PATCH bpf-next 1/3] bpf: Disallow freplace on XDP with mismatched xdp_has_frags values Leon Hwang
2026-03-24 16:18 ` Toke Høiland-Jørgensen
2026-03-25 1:42 ` Leon Hwang
2026-03-25 10:38 ` Toke Høiland-Jørgensen
2026-03-26 19:42 ` Jakub Kicinski
2026-03-27 6:42 ` Leon Hwang
2026-03-28 0:12 ` Jakub Kicinski [this message]
2026-03-30 5:20 ` Leon Hwang
2026-03-24 15:04 ` [PATCH bpf-next 2/3] bpf: Disallow freplace on kprobe with mismatched kprobe_write_ctx values Leon Hwang
2026-03-25 12:51 ` Jiri Olsa
2026-03-25 13:54 ` Leon Hwang
2026-03-27 20:41 ` Jiri Olsa
2026-03-30 5:51 ` Leon Hwang
2026-03-24 15:04 ` [PATCH bpf-next 3/3] selftests/bpf: Add tests to verify freplace compatibility Leon Hwang
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