From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Vagin Subject: Re: [CRIU] linux-next: WARNING: CPU: 0 PID: 2825 at net/ipv4/tcp_input.c:3078 tcp_ack+0x11f5/0x1380() Date: Mon, 11 Aug 2014 19:37:06 +0400 Message-ID: <20140811153706.GD22836@paralelels.com> References: <1407766352.10122.34.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="koi8-r" Cc: Andrey Wagin , "criu@openvz.org" , , Pavel Emelyanov To: Eric Dumazet Return-path: Received: from relay.parallels.com ([195.214.232.42]:50961 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753914AbaHKPhM (ORCPT ); Mon, 11 Aug 2014 11:37:12 -0400 Content-Disposition: inline In-Reply-To: <1407766352.10122.34.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Aug 11, 2014 at 04:12:32PM +0200, Eric Dumazet wrote: > On Mon, 2014-08-11 at 17:35 +0400, Andrey Wagin wrote: > > Hi All, > > > > I execute CRIU tests on linux-next. Today I started to check the tain > > flag and found a warning: > > > > [ 866.469685] Peer 127.0.0.1:46524/8880 unexpectedly shrunk window > > 2532634294:2557500938 (repaired) > > [ 879.562534] ------------[ cut here ]------------ > > [ 879.562947] WARNING: CPU: 0 PID: 2825 at net/ipv4/tcp_input.c:3078 > > tcp_ack+0x11f5/0x1380() > > [ 879.563571] Modules linked in: tun netlink_diag af_packet_diag > > udp_diag tcp_diag inet_diag unix_diag ip6t_rpfilter ip6t_REJECT > > xt_conntrack cfg80211 rfkill ebtable_nat ebtable_broute bridge stp llc > > ebtable_filter ebtables ppdev ip6table_nat nf_conntrack_ipv6 > > nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security > > ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 > > nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle > > iptable_security iptable_raw microcode serio_raw i2c_piix4 parport_pc > > parport nfsd auth_rpcgss nfs_acl lockd sunrpc virtio_blk virtio_net > > virtio_pci virtio_ring virtio ata_generic pata_acpi > > [ 879.567253] CPU: 0 PID: 2825 Comm: socket-tcpbuf-l Not tainted > > 3.16.0-next-20140811 #1 > > [ 879.567829] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > > [ 879.568177] 0000000000000000 00000000c532680c ffff880039643d00 > > ffffffff817aa2d2 > > [ 879.568776] 0000000000000000 ffff880039643d38 ffffffff8109afbd > > ffff880039d6ba80 > > [ 879.569386] ffff88003a449800 000000002983d6bd 0000000000000000 > > 000000002983d6bc > > [ 879.569982] Call Trace: > > [ 879.570264] [] dump_stack+0x4d/0x66 > > [ 879.570599] [] warn_slowpath_common+0x7d/0xa0 > > [ 879.570935] [] warn_slowpath_null+0x1a/0x20 > > [ 879.571292] [] tcp_ack+0x11f5/0x1380 > > [ 879.571614] [] tcp_rcv_established+0x1ed/0x710 > > [ 879.571958] [] tcp_v4_do_rcv+0x10a/0x370 > > [ 879.572315] [] release_sock+0x89/0x1d0 > > [ 879.572642] [] do_tcp_setsockopt.isra.36+0x120/0x860 > > [ 879.573000] [] ? rcu_read_lock_held+0x6e/0x80 > > [ 879.573352] [] tcp_setsockopt+0x32/0x40 > > [ 879.573678] [] sock_common_setsockopt+0x14/0x20 > > [ 879.574031] [] SyS_setsockopt+0x80/0xf0 > > [ 879.574393] [] system_call_fastpath+0x16/0x1b > > [ 879.574730] ---[ end trace a17cbc38eb8c5c00 ]--- > > [ 893.880049] Peer 0000:0000:0000:0000:0000:0000:0000:0001:60450/8880 > > unexpectedly shrunk window 6341700:31207524 (repaired) > > > > During tests a few tcp connections have been repaired. I think the > > problem is around these sockets. I'm going to look what wrong here. > > -- > > Hmmff > > net/ipv4/tcp.c at line 1195 should be updated I guess. Yes. We need to initialize skb->skb_mstamp here. Thanks. > > Although I do not really understand the logic here. > > If we do not have a valid timestamp on repair, why force using current > time ? > > It breaks rtt estimations. Yes, it does. We hope that tcp code will fix rtt according with next packages. ps: Add Pavel in CC. > > > > _______________________________________________ > CRIU mailing list > CRIU@openvz.org > https://lists.openvz.org/mailman/listinfo/criu