From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D2621EC01E for ; Thu, 20 Mar 2025 16:26:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742488011; cv=none; b=gvSj3GK97lKI8RTQgmvj57XPoLwNxIEugbnkpowZV7vdWIdGz0Mx0HrQS/gJL3xJKSq8bJIJFNoilE1ZqL8AxqDrNh18XyXs2BIlsb/CatJkDWxeYuzA9LElsh+0A3a/32wE9g+b+V+GLpMV4yulArpgwBWlj934qBd+5dvFSxc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742488011; c=relaxed/simple; bh=tB4FjmDX422qR/WjfOPcfUAJGkQ6d5tL/RSTCNqydIo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=FQXb5CUT6vbGy4hMUCOIcz//eyI0/p27eOkUNGBo837RUXOp8AYUmdoLP03eAOJeZRUvrioKBg9BXwONR08s5DS8Vc2ObX4+lKm+ic7dzVi3eyq2W1M1r+tvmSf0vY8FvxUXi9uKGiO0l2zTV52QwPY1KF/8SkR/vtRU3jN0XLM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UXlT7Uim; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UXlT7Uim" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA170C4CEDD; Thu, 20 Mar 2025 16:26:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742488010; bh=tB4FjmDX422qR/WjfOPcfUAJGkQ6d5tL/RSTCNqydIo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UXlT7UimKSBFoNra+/+iGfqMauGEefsiOgO3CQcptjiycKP5YVA45GDQclkUUSXhq 0pMQXN7UWCmnmKJoxpa4TEmpVpqgC8/ZYXefxugXbVLtwm2ImF13f7rcjzLJfjVGI3 60izLFv8/qp7VnIib4qcF5RhIt2MkTIXCgOxgEDx2IcZ2+9haScpNrMJ3okchagUxA 2/I0LNz14zDimCa7+0Xzne/CodHaTPAgS+ouCG8h8Z0zumMFQCNLv6Ffzgm/LmfuXO Dv3uknMsmTh0yOH54IyjMTU0xj5oQFFycOBL7EaCHY9BS+mSiHVSRf4me6lxGV0fxF /j3pCe9eCdnuw== Date: Thu, 20 Mar 2025 16:26:46 +0000 From: Simon Horman To: Guillaume Nault Cc: Ido Schimmel , Stanislav Fomichev , David Miller , Jakub Kicinski , Paolo Abeni , Eric Dumazet , netdev@vger.kernel.org, David Ahern , Antonio Quartulli , Petr Machata Subject: Re: [PATCH net v4 1/2] gre: Fix IPv6 link-local address generation. Message-ID: <20250320162646.GC892515@horms.kernel.org> References: <559c32ce5c9976b269e6337ac9abb6a96abe5096.1741375285.git.gnault@redhat.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Mar 17, 2025 at 10:10:45PM +0100, Guillaume Nault wrote: > On Sun, Mar 16, 2025 at 03:08:48PM +0200, Ido Schimmel wrote: > > On Fri, Mar 14, 2025 at 01:18:21PM -0700, Stanislav Fomichev wrote: > > > On 03/14, Guillaume Nault wrote: > > > > On Fri, Mar 14, 2025 at 08:18:32AM -0700, Stanislav Fomichev wrote: > > > > > > > > > > Could you please double check net/forwarding/ip6gre_custom_multipath_hash.sh ? > > > > > It seems like it started falling after this series has been pulled: > > > > > https://netdev-3.bots.linux.dev/vmksft-forwarding-dbg/results/31301/2-ip6gre-custom-multipath-hash-sh/stdout > > > > > > > > Hum, net/forwarding/ip6gre_custom_multipath_hash.sh works for me on the > > > > current net tree (I'm at commit 4003c9e78778). I have only one failure, > > > > but it already happened before 183185a18ff9 ("gre: Fix IPv6 link-local > > > > address generation.") was applied. > > > > > > On my side I see the following (ignore ping6 FAILs): > > > > > > bfc6c67ec2d6 - (net-next/main, net-next/HEAD) net/smc: use the correct ndev to find pnetid by pnetid table (7 hours ago) > > > > > > TAP version 13 > > > 1..1 > > > # timeout set to 0 > > > # selftests: net/forwarding: ip6gre_custom_multipath_hash.sh > > > [ 9.275735][ T167] ip (167) used greatest stack depth: 23536 bytes left > > > [ 13.769300][ T255] gre: GRE over IPv4 demultiplexor driver > > > [ 13.838185][ T255] ip6_gre: GRE over IPv6 tunneling driver > > > [ 13.951780][ T12] ip6_tunnel: g1 xmit: Local address not yet configured! > > > [ 14.038101][ T12] ip6_tunnel: g1 xmit: Local address not yet configured! > > > [ 15.148469][ T281] 8021q: 802.1Q VLAN Support v1.8 > > > [ 17.559477][ T321] GACT probability NOT on > > > [ 18.551876][ T12] ip6_tunnel: g2 xmit: Local address not yet configured! > > > [ 18.633656][ T12] ip6_tunnel: g2 xmit: Local address not yet configured! > > > # TEST: ping [ OK ] > > > # TEST: ping6 [FAIL] > > > # INFO: Running IPv4 overlay custom multipath hash tests > > > # TEST: Multipath hash field: Inner source IP (balanced) [FAIL] > > > # Expected traffic to be balanced, but it is not > > > # INFO: Packets sent on path1 / path2: 1 / 12602 > > > # TEST: Multipath hash field: Inner source IP (unbalanced) [ OK ] > > > # INFO: Packets sent on path1 / path2: 0 / 12601 > > > # TEST: Multipath hash field: Inner destination IP (balanced) [FAIL] > > > # Expected traffic to be balanced, but it is not > > > # INFO: Packets sent on path1 / path2: 1 / 12600 > > > # TEST: Multipath hash field: Inner destination IP (unbalanced) [ OK ] > > > # INFO: Packets sent on path1 / path2: 0 / 12600 > > > ... > > > > > > 8ecea691e844 - (HEAD -> upstream/net-next/main) Revert "gre: Fix IPv6 link-local address generation." (2 minutes ago) > > > > > > TAP version 13 > > > 1..1 > > > # timeout set to 0 > > > # selftests: net/forwarding: ip6gre_custom_multipath_hash.sh > > > [ 13.863060][ T252] gre: GRE over IPv4 demultiplexor driver > > > [ 13.911551][ T252] ip6_gre: GRE over IPv6 tunneling driver > > > [ 15.226124][ T277] 8021q: 802.1Q VLAN Support v1.8 > > > [ 17.629460][ T317] GACT probability NOT on > > > [ 17.645781][ T315] tc (315) used greatest stack depth: 23040 bytes left > > > # TEST: ping [ OK ] > > > # TEST: ping6 [FAIL] > > > # INFO: Running IPv4 overlay custom multipath hash tests > > > # TEST: Multipath hash field: Inner source IP (balanced) [ OK ] > > > # INFO: Packets sent on path1 / path2: 5552 / 7052 > > > # TEST: Multipath hash field: Inner source IP (unbalanced) [ OK ] > > > # INFO: Packets sent on path1 / path2: 12600 / 2 > > > [ 36.278056][ C2] clocksource: Long readout interval, skipping watchdog check: cs_nsec: 1078005296 wd_nsec: 1078004682 > > > # TEST: Multipath hash field: Inner destination IP (balanced) [ OK ] > > > # INFO: Packets sent on path1 / path2: 6650 / 5950 > > > # TEST: Multipath hash field: Inner destination IP (unbalanced) [ OK ] > > > # INFO: Packets sent on path1 / path2: 0 / 12600 > > > ... > > > > > > And I also see the failures on 4003c9e78778. Not sure why we see > > > different results. And the NIPAs fails as well: > > > > > > https://netdev-3.bots.linux.dev/vmksft-forwarding-dbg/results/32922/1-ip6gre-custom-multipath-hash-sh/stdout > > > > I can reproduce this locally and I'm getting the exact same result as > > the CI. All the balanced tests fail because the traffic is forwarded via > > a single nexthop. No failures after reverting 183185a18ff9. > > > > I'm still not sure what happens, but for some reason a neighbour is not > > created on one of the nexthop devices which causes rt6_check_neigh() to > > skip over this path (returning RT6_NUD_FAIL_DO_RR). Enabling > > CONFIG_IPV6_ROUTER_PREF fixes the issue because then RT6_NUD_SUCCEED is > > returned. > > > > I can continue looking into this on Tuesday (mostly AFK tomorrow). > > I finally managed to reproduce the problem using vng. Still no problem > on my regular VM, no matter if I enable CONFIG_IPV6_ROUTER_PREF or not. > I'll continue investigating this problem... FWIIW, I have tried much, but am unable to _reliably_ reproduce this problem.