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 EE821383; Tue, 5 Nov 2024 21:40:17 +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=1730842818; cv=none; b=JPC4TjNKz+Yz/fq8MnrgaGdzk/nHQCZ033AnXQteIBeOZUqTbFFrtKAxmaxTASYqBVZgyEXIWitC3BonouXwIaRYNk344oCp2wpICd4nUSy14oTok3p0gI4DHhjLJemtCH5oF6LeFwi7EJvrebxv/j+paLRtFrSepVE+Vac7Dj4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730842818; c=relaxed/simple; bh=UP801SCt6TwweUNVnTRvtmrXTNs5rIrSYTvgfWg3Vbc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=n/q/5wywAjkTQCUuIJ1vfa9kVRrNdzVdt85TR/38Exqn61LXlLhASMZVwgo5Aoxv4qnpaySEGu1ByUkgG6MeeB44LaND+mCsAWZpzoNZFWPvsv5ZyiHeirrxSAr1RdSMk2TL2fPlGBEIuRWJnU9Ea0lcuNENkGykWhHOXPGGdP4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ecXUWDHP; 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="ecXUWDHP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F30AC4CECF; Tue, 5 Nov 2024 21:40:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730842817; bh=UP801SCt6TwweUNVnTRvtmrXTNs5rIrSYTvgfWg3Vbc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ecXUWDHPRgGCL4vnGUFQFx71O2gPVApWkhc2slPSzqNuPFhgT6Po39ORoD3vyqoY/ R4g5A/kfpwPwNqKrsL8jOCZKwQ3TgNrckTlJWJLIdYdBXNX+Os8MWFS7VkdAt/pe9D NLsQinA+muWXpuJpsZRuw1s9lgsvLlJQ5SnT4EvN2mFVbXr7dvKfhqzjjstW1/KDyC I5J4I13Qfb9eMRhdPHtrGCW49fV9+ywiVleGqQ3cK2rPtmb/1W0roVOpThItvNdBZ4 XMvHV++UYXAEYcNC6h0YruR8cp0GyZWNWX9X1mdF3w2oCUvgyxGkiyzyeqkJhbuMqe 1VMmKTNTB9++w== Message-ID: Date: Tue, 5 Nov 2024 14:40:16 -0700 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 net-next 1/2] ipv6: release nexthop on device removal Content-Language: en-US To: Paolo Abeni , netdev@vger.kernel.org Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Simon Horman , Shuah Khan , linux-kselftest@vger.kernel.org References: <604c45c188c609b732286b47ac2a451a40f6cf6d.1730828007.git.pabeni@redhat.com> From: David Ahern In-Reply-To: <604c45c188c609b732286b47ac2a451a40f6cf6d.1730828007.git.pabeni@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/5/24 11:23 AM, Paolo Abeni wrote: > The CI is hitting some aperiodic hangup at device removal time in the > pmtu.sh self-test: > > unregister_netdevice: waiting for veth_A-R1 to become free. Usage count = 6 > ref_tracker: veth_A-R1@ffff888013df15d8 has 1/5 users at > dst_init+0x84/0x4a0 > dst_alloc+0x97/0x150 > ip6_dst_alloc+0x23/0x90 > ip6_rt_pcpu_alloc+0x1e6/0x520 > ip6_pol_route+0x56f/0x840 > fib6_rule_lookup+0x334/0x630 > ip6_route_output_flags+0x259/0x480 > ip6_dst_lookup_tail.constprop.0+0x5c2/0x940 > ip6_dst_lookup_flow+0x88/0x190 > udp_tunnel6_dst_lookup+0x2a7/0x4c0 > vxlan_xmit_one+0xbde/0x4a50 [vxlan] > vxlan_xmit+0x9ad/0xf20 [vxlan] > dev_hard_start_xmit+0x10e/0x360 > __dev_queue_xmit+0xf95/0x18c0 > arp_solicit+0x4a2/0xe00 > neigh_probe+0xaa/0xf0 > > While the first suspect is the dst_cache, explicitly tracking the dst > owing the last device reference via probes proved such dst is held by > the nexthop in the originating fib6_info. > > Similar to commit f5b51fe804ec ("ipv6: route: purge exception on > removal"), we need to explicitly release the originating fib info when > disconnecting a to-be-removed device from a live ipv6 dst: move the > fib6_info cleanup into ip6_dst_ifdown(). > > Tested running: > > ./pmtu.sh cleanup_ipv6_exception > > in a tight loop for more than 400 iterations with no spat, running an > unpatched kernel I observed a splat every ~10 iterations. > > Fixes: f88d8ea67fbd ("ipv6: Plumb support for nexthop object in a fib6_info") are you sure that is the correct Fixes? That commit is June 2019 and there have been stable periods since then without netdev release problems. > Signed-off-by: Paolo Abeni > --- > v1 -> v2: > - dropped unintended whitespace change > --- > net/ipv6/route.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > Reviewed-by: David Ahern