From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Weiming Shi" <bestswngs@gmail.com>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"John Fastabend" <john.fastabend@gmail.com>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Eduard Zingerman" <eddyz87@gmail.com>,
"Kumar Kartikeya Dwivedi" <memxor@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>,
"Ihor Solodrai" <ihor.solodrai@linux.dev>,
"David S . Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Simon Horman" <horms@kernel.org>,
"Shuah Khan" <shuah@kernel.org>
Cc: linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
netdev@vger.kernel.org, linux-kselftest@vger.kernel.org,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Peter Oskolkov" <posk@google.com>, "Xiang Mei" <xmei5@asu.edu>,
stable@vger.kernel.org
Subject: Re: [PATCH v3 1/3] bpf: propagate cb_access from freplace programs
Date: Sun, 20 Sep 2026 17:06:40 +0000 [thread overview]
Message-ID: <DLKB3QCTZH4F.243J1I4BAEBOA@gmail.com> (raw)
In-Reply-To: <20260920163211.795547-2-bestswngs@gmail.com>
On Mon, Sep 21, 2026 at 12:32 AM Weiming Shi <bestswngs@gmail.com> wrote:
> Cc: stable@vger.kernel.org
> Fixes: be8704ff07d2 ("bpf: Introduce dynamic program extensions")
That shouldn't go to stable. Loading an EXT prog takes CAP_BPF +
CAP_NET_ADMIN + CAP_PERFMON.
[...]
> + if (prog->type == BPF_PROG_TYPE_EXT && READ_ONCE(prog->cb_access)) {
> + WRITE_ONCE(tgt_prog->cb_access, true);
> + /* Drain runs that observed cb_access=false before enabling freplace. */
> + synchronize_rcu();
> + }
tc doesn't look at cb_access at all, yet every tc freplace that touches
cb[] now waits for an RCU grace period in attach.
This is a separate issue from the LWT one. Patch 2 resets the cb after
the run whether the prog has cb_access or not, so it doesn't depend on
this patch. Pls drop it from this series.
next prev parent reply other threads:[~2026-09-20 17:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-20 16:32 [PATCH v3 0/3] bpf: clear stale IPv4 options after LWT encapsulation Weiming Shi
2026-09-20 16:32 ` [PATCH v3 1/3] bpf: propagate cb_access from freplace programs Weiming Shi
2026-09-20 17:06 ` Alexei Starovoitov [this message]
2026-09-20 17:07 ` Alexei Starovoitov
2026-09-20 16:32 ` [PATCH v3 2/3] bpf: clear stale IPv4 options after LWT encapsulation Weiming Shi
2026-09-20 17:06 ` Alexei Starovoitov
2026-09-20 16:32 ` [PATCH v3 3/3] selftests/bpf: cover stale CB after LWT IP encapsulation Weiming Shi
2026-09-20 17:06 ` Alexei Starovoitov
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