From patchwork Mon Feb 3 14:30:34 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 13957603 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-qt1-f202.google.com (mail-qt1-f202.google.com [209.85.160.202]) (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 532DB20E014 for ; Mon, 3 Feb 2025 14:30:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738593056; cv=none; b=PEtyrzmXtzwJzjzMitUEVuXr640FmDNAtTtZ4j9u9U5GfC1WOUD/7mKqKdUDEe/L5z3NGBSXsBwNnulgDITqCERL1RHYZRzrXfYMfS7QNyv68holCILlqafOZXScafLwN2lot4389gH2hC4p1d4rmoLrJyYLGErmzbJMZ8h7/Ws= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738593056; c=relaxed/simple; bh=H8JH/QPjFfGxbrJtRbDkCum9cREuE5YKVIPC//b1qCs=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=LFyK+VQoL26URaE5ADff6Nw7pdbjmMuRg3zRJjhP2J+M0RqAvC+1L9LYwRsgy8PZYoqbm59I0aoML4QEV/7s9LxDxMKnvb9Xfb47Vt3JXuTuKqia+o7PfrMbWIPE062LxavX5MKvXZjqFPaT+L26Y61F+tb7W1DG9Xj6YJAicgE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ORNt+o9z; arc=none smtp.client-ip=209.85.160.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ORNt+o9z" Received: by mail-qt1-f202.google.com with SMTP id d75a77b69052e-46dd301a429so95543511cf.1 for ; Mon, 03 Feb 2025 06:30:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1738593054; x=1739197854; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=oummPnO89bchIzAktiowh3Jl3EZAt201EnCE7gdN6jc=; b=ORNt+o9zNiB5qjfH6HEHOfKX3/EDhOXZ2UGkfz0q8va5LSkzUKi8KTuPyf3ZsI6iIR ZkzJ2LOWzqFzSosOw/xrE6p64e81R6CGN2JpmMwE54J85m9oFqQMln7TgIi9He9T65ct dK/3lN4voLfqJV9ih0cCmt0qqjqJRy5uA1FA/maTuFXv5dTy26fb+awHld5kRxoDBV1u w07LRIxpR/+1QzwiG5vTQ6a603wUmFhezNAoZxPlV5krUK7WrDU0I+cYXv92AQMeViBs uuWAi/wMizhZQhm9D492hby3vId2NGEz0wsxooBtxlUw1n/tdh0QfTE2m/emQBiXiMWh bcnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738593054; x=1739197854; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=oummPnO89bchIzAktiowh3Jl3EZAt201EnCE7gdN6jc=; b=X3uFdBIJTZBZATnAPWbd2j9uvoj4BHhJ9e5og7yEHAtPKBKoTQafJzMC2n7meVtKzS ZxGQJUcQc90/3taEidw0qot8kmrjyw0Hn32V3az73mnzIKbgZcyKOoOMFMFwpncjNZXc lZXDXqS0CWPiRNSGJKNYzmPA++3CezqxjpEm4ot/gg6ymvJZEe+JpPLMsFBUc29xFWV0 084YgjF+XDBK6VtFXBLUMu7C4g6LxJax7TLDR0riWpPp0ljMP/3Ultfr6RRm+G98Z1Jk qotk5mmw29NDxD1vJm/jlEQc2aLUS4ewJkIRI8GRkhyPKahtngYa1oKKYV19ZUpU7zb9 1aVA== X-Gm-Message-State: AOJu0Yyn5e9oOJp1njwH6d2PLvB6linPHcsoNW9aHSoZnnMXtX1TNWo+ f4ZLyJZlEiCQUuuCNn0mh2B2kbbavtc8IQft1C0/OXUXI2HGoTRrS8OFq2tuegzB0CY8LT9oGer 57UUFZmjAIA== X-Google-Smtp-Source: AGHT+IFTe7ZfY4yWX2ICd+1ng3slGad8C5b2GR/bnJKwcPtGGj4cO3rk0SfNRTC0P2RjB2pPcKhR9q+H2bXOMw== X-Received: from qtbay26.prod.google.com ([2002:a05:622a:229a:b0:467:84a6:b744]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:ac8:5702:0:b0:46c:7188:e3c4 with SMTP id d75a77b69052e-46fd09e25aemr209240181cf.10.1738593054306; Mon, 03 Feb 2025 06:30:54 -0800 (PST) Date: Mon, 3 Feb 2025 14:30:34 +0000 In-Reply-To: <20250203143046.3029343-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250203143046.3029343-1-edumazet@google.com> X-Mailer: git-send-email 2.48.1.362.g079036d154-goog Message-ID: <20250203143046.3029343-5-edumazet@google.com> Subject: [PATCH v2 net 04/16] ipv4: use RCU protection in ipv4_default_advmss() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, Kuniyuki Iwashima , Simon Horman , eric.dumazet@gmail.com, Eric Dumazet X-Patchwork-Delegate: kuba@kernel.org ipv4_default_advmss() must use RCU protection to make sure the net structure it reads does not disappear. Fixes: 2e9589ff809e ("ipv4: Namespaceify min_adv_mss sysctl knob") Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima --- net/ipv4/route.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 577b88a43293aa801c3ee736d7e5cc4d97917717..74c074f45758be5ae78a87edb31837481cc40278 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1307,10 +1307,15 @@ static void set_class_tag(struct rtable *rt, u32 tag) static unsigned int ipv4_default_advmss(const struct dst_entry *dst) { - struct net *net = dev_net(dst->dev); unsigned int header_size = sizeof(struct tcphdr) + sizeof(struct iphdr); - unsigned int advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, - net->ipv4.ip_rt_min_advmss); + unsigned int advmss; + struct net *net; + + rcu_read_lock(); + net = dev_net_rcu(dst->dev); + advmss = max_t(unsigned int, ipv4_mtu(dst) - header_size, + net->ipv4.ip_rt_min_advmss); + rcu_read_unlock(); return min(advmss, IPV4_MAX_PMTU - header_size); }