From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: passt.top; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=bCIyNiFX; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by passt.top (Postfix) with ESMTPS id D965A5A0265 for ; Tue, 26 May 2026 12:15:11 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1779790510; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FI/CSQM7GLLf/mwDjaN/BuRU4qytYI0E7C3Rp/nruWU=; b=bCIyNiFXa8frqykHwzoHtcBBnqqlqxt4MJGGhkfBanhNeMfYN6hch3NEeA8xh/Tp+2Fm62 0FesdwodxSf9SLlB2wTWc48ybfgzzmXmHBINanO4pSGkvkvngNCxPirwVpgByXghQwq/Eq 8VGWAye1tQvwxikdOvgeLUIbNZruZU4= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-91-NHlJ9As3N4eCCNcC0oWq_Q-1; Tue, 26 May 2026 06:15:09 -0400 X-MC-Unique: NHlJ9As3N4eCCNcC0oWq_Q-1 X-Mimecast-MFC-AGG-ID: NHlJ9As3N4eCCNcC0oWq_Q_1779790508 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-48fed2519daso48259305e9.0 for ; Tue, 26 May 2026 03:15:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779790508; x=1780395308; h=date:content-transfer-encoding:mime-version:organization:references :in-reply-to:message-id:subject:cc:to:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=FI/CSQM7GLLf/mwDjaN/BuRU4qytYI0E7C3Rp/nruWU=; b=UGwbnQDMjK1dBq+WQne8s4b0fHTmS7Ri2B+cdUu0BtKtZCkzwqg9NRSQFLUzvUQpbb P8bYiGoyY9nGWSOUS2XhblXPtKqBmPrCwI1BUEYW8JZD/40LyufFnNh6wg/lGBmAsEZx FvhNOT3DdqqjympKD/ReAuSzhc6LII72j+drBtaKr/DNpg2DddTSr6PQaLbtlM7pCWxs 1f/PmfDQcrdXFrJsAQKm+82wNQWQKybj1QN1Pe2ROYmkkUWex5tmqrD3fA8rNhhofmXS ow5VOlE/XoF2NRNlJY3dL3sZk5jJ4IIgcVBrgE8dglDTBZG8kotHppCIVLjWg8ScLg69 IZ3Q== X-Gm-Message-State: AOJu0Yx2Vy77lSwvdK8fN86TorIcOE2gQ2E+T/nnVHDGX085ovBUVce0 zbo0RVXCPmybeEPVlERj01ghJtICPfWvprtxztOaiFcBtgiWuzdyleYKgxEvz0AYSWrtFTlvLTm MZTLqjnGQ4rUycAdvwO/6mb3Pp5W8ouDNyV1ZT6H98WcYj0rAsVm4Ug== X-Gm-Gg: Acq92OFPU5wBog4rLkXZc71v+NuAtLzP3uV4kfN/dhnLkx8ntSr5sJzXM7TdguXB4mN cb3AOd1l/5whVqw0+Hkl2TI2vLgsuZmp8PzLextpybqUiya/yGIR3gNkPixv/eOC541GKnQv3+e YdxOJzhg1o7P57Y6R3rpkLJbyjnyA+rSK/rr+vVZbnxd1mdAnFsgRoPCiEQ7vPJJBBA13PHQP+e e/WXEHUbwgoT2q+BIcxnVM5tHKD9q3mplTSBcTEIonR5EbbWaM9olGASmWgjze6VxGoFTN7eUVa z7GkGb0StDLQ6S0bJFdUdb88JvILUSTHxcmtzscQZjkr47+fcdi9JD+yywDPjGcEa4ZfHbgrtSk e6D1HBkjrYsKkQ7yWDsSBIxLwe4qpwf64 X-Received: by 2002:a05:600c:4591:b0:490:6869:46c6 with SMTP id 5b1f17b1804b1-490686947a8mr102790985e9.31.1779790507643; Tue, 26 May 2026 03:15:07 -0700 (PDT) X-Received: by 2002:a05:600c:4591:b0:490:6869:46c6 with SMTP id 5b1f17b1804b1-490686947a8mr102790245e9.31.1779790507103; Tue, 26 May 2026 03:15:07 -0700 (PDT) Received: from maya.myfinge.rs (ifcgrfdd.trafficplex.cloud. [2a10:fc81:a806:d6a9::1]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-490417aeaecsm142015115e9.4.2026.05.26.03.15.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 May 2026 03:15:06 -0700 (PDT) From: Stefano Brivio To: David Gibson Subject: Re: [PATCH 1/2] netlink: Use regular request/response netlink socket for initial neighbour sync Message-ID: <20260526121504.4bfa9d0e@elisabeth> In-Reply-To: References: <20260521180146.1834333-1-sbrivio@redhat.com> <20260521180146.1834333-2-sbrivio@redhat.com> Organization: Red Hat X-Mailer: Claws Mail 4.2.0 (GTK 3.24.49; x86_64-pc-linux-gnu) MIME-Version: 1.0 Date: Tue, 26 May 2026 12:15:05 +0200 (CEST) X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 84eC4MzgbkcwQLSiEzXW_m4ZDbxzuv2vxts7p4Em-qI_1779790508 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: LLZRH7G5EQI26UMO6ECTMYVLHYWVS3RW X-Message-ID-Hash: LLZRH7G5EQI26UMO6ECTMYVLHYWVS3RW X-MailFrom: sbrivio@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: passt-dev@passt.top, Jon Maloy , Paul Holzinger X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Fri, 22 May 2026 10:02:27 +1000 David Gibson wrote: > On Thu, May 21, 2026 at 08:01:45PM +0200, Stefano Brivio wrote: > > ...instead of the one dedicated to the neighbour monitor, because, if > > neighbour notifications start coming in before or while we send the > > initial request to read out the neighbour tables, messages and > > sequence numbers will collide. > > > > For example, if nl_neigh_sync() sends a RTM_GETNEIGH request with > > sequence 20, we expect a corresponding reply with sequence 20. But > > given that we already used the same socket to subscribe to > > notifications, and notifications don't correspond to any specific > > request we sent, we might now get a message with sequence 0. > > Heh. Called it, kinda. Nice job tracking this down. Your suggestion that we were probably mixing up messages helped as a starting point. Then I think we concluded that _of course_ it's different sockets and they can't influence each other. So I started looking into how two netlink sockets belonging to the same process could possibly interfere with each other, until I tried to skip the creation of nl_neigh_sock and realised that nl_neigh_sync() stopped working altogether... oops. -- Stefano