From: Jakub Sitnicki <jakub@cloudflare.com>
To: Michal Luczaj <mhal@rbox.co>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
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>,
John Fastabend <john.fastabend@gmail.com>,
Stanislav Fomichev <sdf@fomichev.me>,
"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>,
Jiayuan Chen <jiayuan.chen@linux.dev>,
Kuniyuki Iwashima <kuniyu@google.com>,
Willem de Bruijn <willemb@google.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH bpf-next 2/2] bpf, sockmap: Use sock_hold() instead of refcount_inc_not_zero() in lookup
Date: Fri, 14 Aug 2026 12:42:37 +0200 [thread overview]
Message-ID: <877blt0yqq.fsf@cloudflare.com> (raw)
In-Reply-To: <20260813-sockmap-lookup-get-ref-v1-2-31f5d55f44ac@rbox.co> (Michal Luczaj's message of "Thu, 13 Aug 2026 14:42:00 +0200")
On Thu, Aug 13, 2026 at 02:42 PM +02, Michal Luczaj wrote:
> psock's hold on the looked up socket isn't dropped until sk_psock_drop() ->
> queue_rcu_work() -> sk_psock_destroy() runs, which happens only after the
> entry is unlinked and an RCU grace period elapses. Since the lookup runs
> under RCU, a non-NULL result guarantees sk_refcnt >= 1:
> refcount_inc_not_zero() can never fail here. Use sock_hold() instead.
>
> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
> Signed-off-by: Michal Luczaj <mhal@rbox.co>
> ---
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
next prev parent reply other threads:[~2026-08-14 10:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-13 12:41 [PATCH bpf-next 0/2] bpf: Cleanup & optimization Michal Luczaj
2026-08-13 12:41 ` [PATCH bpf-next 1/2] bpf: Extract shared reqsk-to-listener upgrade Michal Luczaj
2026-08-13 12:42 ` [PATCH bpf-next 2/2] bpf, sockmap: Use sock_hold() instead of refcount_inc_not_zero() in lookup Michal Luczaj
2026-08-14 10:42 ` Jakub Sitnicki [this message]
2026-08-14 10:45 ` [PATCH bpf-next 0/2] bpf: Cleanup & optimization Jakub Sitnicki
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