Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752193AbdDKQkC (ORCPT ); Tue, 11 Apr 2017 12:40:02 -0400 Received: from mail-qt0-f196.google.com ([209.85.216.196]:32893 "EHLO mail-qt0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751101AbdDKQkA (ORCPT ); Tue, 11 Apr 2017 12:40:00 -0400 MIME-Version: 1.0 In-Reply-To: <20170411104048.2lef7jl4f4qxqct3@alphalink.fr> References: <20170411104048.2lef7jl4f4qxqct3@alphalink.fr> From: R Parameswaran Date: Tue, 11 Apr 2017 09:39:58 -0700 Message-ID: Subject: Re: [PATCH net-next v5 2/2] L2TP:Adjust intf MTU, add underlay L3, L2 hdrs. To: Guillaume Nault Cc: Linux Kernel Network Developers , James Chapman , kleptog@svana.org, Nachi Prachanda , Robert Shearman , Stephen Hemminger , Sven-Thorsten Dietrich , Chas Williams III , Luca Boccassi , Derek Fawcus , Bill Hong , Jan Blunck , David Miller , LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id v3BGe6dE003937 Content-Length: 3865 Lines: 75 Hi Guillaume, On Tue, Apr 11, 2017 at 3:40 AM, Guillaume Nault wrote: > On Wed, Apr 05, 2017 at 05:00:07PM -0700, R. Parameswaran wrote: >> >> Change-set here uses the new kernel function, kernel_sock_ip_overhead(), >> to factor the outer IP overhead on the L2TP tunnel socket (including >> IP Options, if any) when calculating the default MTU for an Ethernet >> pseudowire, along with consideration of the inner Ethernet header. >> > I get the following warning with CONFIG_LOCKDEP when creating a new > session: > # ip l2tp add tunnel local 10.1.8.64 remote 10.1.8.32 udp_sport 1701 udp_dport 1701 tunnel_id 1 peer_tunnel_id 1 > # ip l2tp add session tunnel_id 1 session_id 1 peer_session_id 1 > ... Thanks for reporting this - I'll try and put up a patch soon, hopefully the patch can stay in while I add this. One Q - how many CPU cores do you have? Can you give me some idea of how many tunnels and sessions when you saw this? I did not see this warning in my testing, possibly because CONFIG_LOCKDEP_SUPPORT is turned off on the product build? Will re-test with this turned on. thanks, Ramkumar > [ 45.524535] ------------[ cut here ]------------ > [ 45.524570] WARNING: CPU: 3 PID: 732 at ./include/net/sock.h:1509 kernel_sock_ip_overhead+0x54/0x1a1 > [ 45.524574] Modules linked in: l2tp_eth l2tp_netlink l2tp_core ip6_udp_tunnel udp_tunnel crc32c_intel ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd cryptd glue_helper evdev acpi_cpufreq processor button serio_raw ext4 crc16 jbd2 mbcache virtio_blk virtio_net virtio_pci virtio_ring virtio > [ 45.524696] CPU: 3 PID: 732 Comm: ip Not tainted 4.11.0-rc5 #1 > [ 45.524700] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 > [ 45.524704] Call Trace: > [ 45.524714] dump_stack+0x67/0x90 > [ 45.524725] __warn+0xfd/0x118 > [ 45.524739] warn_slowpath_null+0x18/0x1a > [ 45.524747] kernel_sock_ip_overhead+0x54/0x1a1 > [ 45.524761] l2tp_eth_create+0x1eb/0x557 [l2tp_eth] > [ 45.524768] ? __mutex_unlock_slowpath+0xb5/0x2c2 > [ 45.524787] ? l2tp_eth_dev_uninit+0xd9/0xd9 [l2tp_eth] > [ 45.524800] l2tp_nl_cmd_session_create+0x521/0x56b [l2tp_netlink] > [ 45.524827] genl_family_rcv_msg+0x445/0x4b3 > [ 45.524857] genl_rcv_msg+0x60/0x84 > [ 45.524867] ? genl_family_rcv_msg+0x4b3/0x4b3 > [ 45.524875] netlink_rcv_skb+0x95/0x102 > [ 45.524881] ? down_read+0x41/0x62 > [ 45.524893] genl_rcv+0x23/0x32 > [ 45.524901] netlink_unicast+0x1b0/0x23b > [ 45.524915] netlink_sendmsg+0x46f/0x48f > [ 45.524933] ? netlink_unicast+0x23b/0x23b > [ 45.524942] sock_sendmsg_nosec+0x41/0x51 > [ 45.524953] sock_sendmsg+0x33/0x38 > [ 45.524962] ___sys_sendmsg+0x2a0/0x374 > [ 45.524991] ? do_raw_spin_unlock+0xc2/0xcc > [ 45.525002] ? _raw_spin_unlock+0x22/0x25 > [ 45.525014] ? match_held_lock+0x20/0x113 > [ 45.525027] ? __fget_light+0x89/0xae > [ 45.525045] __sys_sendmsg+0x40/0x6b > [ 45.525052] ? __sys_sendmsg+0x40/0x6b > [ 45.525075] SyS_sendmsg+0x9/0xb > [ 45.525083] entry_SYSCALL_64_fastpath+0x18/0xad > [ 45.525089] RIP: 0033:0x7fb224391690 > [ 45.525094] RSP: 002b:00007ffe53943dd8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > [ 45.525104] RAX: ffffffffffffffda RBX: 00007ffe539480f0 RCX: 00007fb224391690 > [ 45.525108] RDX: 0000000000000000 RSI: 00007ffe53943e20 RDI: 0000000000000004 > [ 45.525113] RBP: ffffffff810a1e49 R08: 0000000000000000 R09: 0000000000000005 > [ 45.525119] R10: 0000000000000000 R11: 0000000000000246 R12: ffff88003436ff98 > [ 45.525124] R13: 0000000000000046 R14: 00007ffe539486a0 R15: 00007ffe53947ea0 > [ 45.525136] ? trace_hardirqs_off_caller+0x121/0x12f > [ 45.525157] ---[ end trace 0834023e7b30e761 ]--- > > I guess you neet to lock_sock(tunnel->socket) before calling > kernel_sock_ip_overhead().