From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f45.google.com (mail-ej1-f45.google.com [209.85.218.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4FB08221271 for ; Thu, 20 Nov 2025 12:58:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763643508; cv=none; b=pr+fNQmXWhhaPnqrbScP7oj0gzccEEcPOLKQJ8qKg051Qeo8ug5N6+0J7E6dJvAyILHux/ul0JLIx8ebaSEfJo8YqBVoR5dAo98flNiawCCFuCIVRmBv3kXvKFVIe6DxpS/GCHBU3rOCpHZgTsZJe7y9AbRbTOKD9ioeKS3an18= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763643508; c=relaxed/simple; bh=yrrGT9RTCWN6v25Jy1PljEJyV2gwJA+0BkSczHJvwqU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=JK4FEN71YWHcDvL8KnllQVASVDnBxFB9T67b+yXaYCjT78dNXjqHor2aDnTWySQhs2LXOPSQEdU5laSMl6lHW7on+kgEbM1zejfmBn1I11xosGn203FgUuZ+xCTJ0Wd0q6kBkMYvNMRzgm+e4U+fM5Z4PF7lNiRjE39303IjuOw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com; spf=pass smtp.mailfrom=cloudflare.com; dkim=pass (2048-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b=fYrXX8xb; arc=none smtp.client-ip=209.85.218.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=cloudflare.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="fYrXX8xb" Received: by mail-ej1-f45.google.com with SMTP id a640c23a62f3a-b735b7326e5so348936566b.0 for ; Thu, 20 Nov 2025 04:58:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google09082023; t=1763643504; x=1764248304; darn=vger.kernel.org; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:from:to:cc:subject:date:message-id:reply-to; bh=rWt1WezTZ5DpLX3MB7doQs98ekhplq8AtMdx/O/O2yc=; b=fYrXX8xbFJfVWCjK5Q7GUyJO18BeKxiwADRU5K+rrAA6u15mgWImhHaeMEBG8ru7Dd 7HSXcuvoEK/QfVILofmsTJ4S2bqK6ziihlf0MQI14VbZhiO87r9+dhHQc3a3UakvS8hv z+KFaUHRVE8FXa/86ghRx/YovLnMiGQWSsSC9NnnVx5Z2wA2kZl+oD31/2IPLFjdsIGC 6aNJ1PAEVPQ/nrI36XWMxL4NcdpQaEwC/H7e6sdCYA+nkl/WZv+XUqZTI1+8Y0H6AKPD gyNN531KzyCx2Vr4Fuw5O3nD3UZP5scepYagez/cn4rrVnSC+qxd2cLViMifGlDmkRaf gQIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763643504; x=1764248304; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=rWt1WezTZ5DpLX3MB7doQs98ekhplq8AtMdx/O/O2yc=; b=u5cxd/8lhPcweY+uUc6ENpGFjWf1ZPJpolAmAM6SJFqMi1P1A4hSq/u/zvJcUIC/+y 5ZNeTiuqJ1sPpWLkrsaP/+s2UnNQq9wYt/0YlfX5JLXEKdZqfFB+griMjdJU7BisH5bq nMgkX/zROtVs4SnxrkEUs3OxtKt/S9fADx42xQZXCxbP79pgSSS+0eIOwwPQeSvfqQm0 qkokJ0CiKo/ayJDEFvdkQYS78uyHNdqLYmP1dcBh/G/6Y4pdu23SBCXOUC5X5IoFuP6C S94sUZxJy8KKq2CT1r8GsBxlZHeJxGR88mheK4MWTwdIwBF6skHpoKIBXaoIcXYFJyoh EZKQ== X-Forwarded-Encrypted: i=1; AJvYcCXtPJiOgDo1L3ttaEoScQGLzuTVWlh6apNN8NqTcKkVW/590rdWWZRQn5UgJOOChprdqQ2iB7KkuOFXUn0=@vger.kernel.org X-Gm-Message-State: AOJu0YyG9GJYwZ2M8BQjVoaSYozKxbtswvU/w/Bbk/kOKCMDZiWCXzzZ VvZWd+I1/l3JMdq/f1f0LjPJGQymhE5zHWv0StfDOs6YJ2LTKJ3MHhkRe3xyPnG/rOw= X-Gm-Gg: ASbGncvRR7ehPN9lLfXaiQdZWgwtSVpGQJ4YQVHoGNMYTzP/hWXyfavVQGZFjSJFwcm IQRYww07CaI1600lfqHJo8o8YadXuUEy/QotYUnPv4c321zF8AEZN+WAzllaR7eqHu38+z6+rKf 3t9YJGM5yFUJ0HYhGHbhwbgRvTlWRbVZH+TY+wTriNNmfJyurZPNqu85JjpdVqAx0Lg/PDzlc5F 1cLmqVWiuFG8/NXSrsbNL+yN99jPfQ9WfS25+Lacf4yexOfwSoHma23pdi0ympXHip9ropDsctv rrLjKM3oDN1M0+g61syaVdESXwkyzKz1J2q+wtB80z1laqIki22WGFOt6yetYvfpnAPWBiV13up LqFox0kXMkwHGKoZn4vbwnxuE5mB3cUTmUu5bqGGFcHAW7NJlgQf6wJ6BR6RCU4tl9xHvV25F3Z bAXy4= X-Google-Smtp-Source: AGHT+IGx1D4Lf3+ONX9DYRjufCOc1Fw/EfSu7B0mNDhtvWXtJYLURbexh3sFGvbZtkfpHNbDzHlRQg== X-Received: by 2002:a17:907:9487:b0:b04:48b5:6ea5 with SMTP id a640c23a62f3a-b765720a6e1mr306820066b.17.1763643504589; Thu, 20 Nov 2025 04:58:24 -0800 (PST) Received: from cloudflare.com ([2a09:bac5:5063:2387::38a:71]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b7654fd4e51sm201000466b.42.2025.11.20.04.58.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Nov 2025 04:58:23 -0800 (PST) From: Jakub Sitnicki To: "Jiayuan Chen" Cc: bpf@vger.kernel.org, "John Fastabend" , "David S. Miller" , "Eric Dumazet" , "Jakub Kicinski" , "Paolo Abeni" , "Simon Horman" , "Neal Cardwell" , "Kuniyuki Iwashima" , "David Ahern" , "Alexei Starovoitov" , "Daniel Borkmann" , "Andrii Nakryiko" , "Martin KaFai Lau" , "Eduard Zingerman" , "Song Liu" , "Yonghong Song" , "KP Singh" , "Stanislav Fomichev" , "Hao Luo" , "Jiri Olsa" , "Shuah Khan" , "Michal Luczaj" , "Stefano Garzarella" , "Cong Wang" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH bpf-next v1 1/3] bpf, sockmap: Fix incorrect copied_seq calculation In-Reply-To: <5a66955891ef8db94b7288bbb296efcc0ac357cf@linux.dev> (Jiayuan Chen's message of "Thu, 20 Nov 2025 02:49:43 +0000") References: <20251117110736.293040-1-jiayuan.chen@linux.dev> <20251117110736.293040-2-jiayuan.chen@linux.dev> <87zf8h6bpd.fsf@cloudflare.com> <5a66955891ef8db94b7288bbb296efcc0ac357cf@linux.dev> Date: Thu, 20 Nov 2025 13:58:23 +0100 Message-ID: <87tsyo6ets.fsf@cloudflare.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Thu, Nov 20, 2025 at 02:49 AM GMT, Jiayuan Chen wrote: > November 20, 2025 at 03:53, "Jakub Sitnicki" wrote: > > [...] >> > +/* The BPF program sets BPF_F_INGRESS on sk_msg to indicate data needs to be >> > + * redirected to the ingress queue of a specified socket. Since BPF_F_INGRESS is >> > + * defined in UAPI so that we can't extend this enum for our internal flags. We >> > + * define some internal flags here while inheriting BPF_F_INGRESS. >> > + */ >> > +enum { >> > + SK_MSG_F_INGRESS = BPF_F_INGRESS, /* (1ULL << 0) */ >> > + /* internal flag */ >> > + SK_MSG_F_INGRESS_SELF = (1ULL << 1) >> > +}; >> > + >> > >> I'm wondering if we need additional state to track this. >> Can we track sk_msg's construted from skb's that were not redirected by >> setting `sk_msg.sk = sk` to indicate that the source socket is us in >> sk_psock_skb_ingress_self()? > > Functionally, that would work. However, in that case, we would have to hold > a reference to sk until the sk_msg is read, which would delay the release of > sk. One concern is that if there is a bug in the read-side application, sk > might never be released. We don't need to grab a reference to sk if we're talking about setting it only in sk_psock_skb_ingress_self(). psock already holds a ref for psock->sk, and we purge psock->ingress_msg queue when destroying the psock before releasing the sock ref in sk_psock_destroy(). While there's nothing wrong with an internal flaag, I'm trying to see if we make things somewhat consistent so as a result sk_msg state is easier to reason about. My thinking here is that we already set sk_msg.sk to source socket in sk_psock_msg_verdict() on sendmsg() path, so we know that this is the purpose of that field. We could mimic this on recvmsg() path.