On Fri, Sep 11, 2015 at 06:04:51AM -0700, Eric Dumazet wrote: > On Fri, 2015-09-11 at 12:38 +0100, Russell King - ARM Linux wrote: > > I have a recent Marvell Armada 388 board here which uses the mvneta > > driver. I'm seeing some weird effects with NFS with it acting as a > > client. Unfortunately, the board does not have a functional RTC. > > > > The NFS server is the same NFS server that I've used for years with > > multiple other clients (it's my main NFS server) and it continues to > > support all other clients without any ill effect. The NFS server > > kernel is rather old now, being a 3.x kernel. > > > > The NFS client appears to connect using TCP/IPv6 and initially is > > accessible. Everything appears to work normally, and then the NFS > > server appears to stop responding. > > > > Running tcpdump on the NFS server, and then dumping the captured > > packets > > with tshark (because tcpdump appears not to understand IPv6 SYNs on > > the > > NFS port) shows: > > > > 3 0.030036 armada388 -> n2100 TCP 843→nfs [SYN] Seq=936803106 > > Win=28800 Len=0 MSS=1440 SACK_PERM=1 TSval=892366 TSecr=0 WS=128 > > > 4 0.030409 n2100 -> armada388 TCP nfs→843 [SYN, ACK] Seq=409465870 > > Ack=936803107 Win=28560 Len=0 MSS=1440 SACK_PERM=1 > > TSval=818169117 TSecr=892366 WS=64 > > > 5 0.030493 armada388 -> n2100 TCP [TCP Port numbers reused] > > 843→nfs [SYN] Seq=936803633 Win=28800 Len=0 MSS=1440 SACK_PERM=1 > > TSval=892366 TSecr=0 WS=128 > > Yes, this packet looks very wrong. Like two simultaneous connect with > same source port. It is not a retransmit (Seq numbers differ) > > > 6 0.030699 n2100 -> armada388 TCP nfs→843 [RST, ACK] Seq=0 > > Ack=936803634 Win=0 Len=0 > > 7 0.030766 armada388 -> n2100 TCP 843→nfs [RST] Seq=936803107 > > Win=0 Len=0 > > I suspect port reuse in NFS being broken. > > Have you tried to apply Thanks, I'll give this a go and report back. I've been trying to debug this unsuccessfully. It's really not helpful to enable rpc debugging, and then be greeted with this from printk: [ 2760.156924] RPC: state 4 conn 1 dead 0 zapped 1 sk_shutdown 3 [ 2760.163218] RPC: xs_tcp_state_change client ee240800... [ 2760.168976] RPC: state 5 conn 0 dead 0 zapped 1 sk_shutdown 3 [ 2760.175273] RPC: xs_tcp_state_change client ee240800... [ 2760.181032] RPC: state 7 conn 0 dead 0 zapped 1 sk_shutdown 3 [ 2760.187315] RPC: disconnected transport ee240800 [ 2760.192467] RPC: xs_tcp_state_change client ee240800... [ 2760.198224] RPC: state 7 conn 0 dead 0 zapped 1 sk_shutdown 3 [ 2760.204505] RPC: disconnected transport ee240800 [ 2760.209653] RPC: xs_tcp_data_ready... [ 2760.215001] RPC: wake_up_first(ee240918 "xprt_sending") lspci -vvx |less [ 2805.912330] RPC: looking up Generic cred [ 2805.916791] RPC: looking up Generic cred [ 2805.921259] RPC: looking up Generic cred [ 2805.921784] RPC: looking up Generic cred [ 2805.921787] RPC: looking up Generic cred [ 2805.921788] RPC: looking up Generic cred [ 2805.921792] RPC: new task initialized, procpid 327 [ 2805.921794] RPC: allocated task ee358300 [ 2805.921797] RPC: 1335 __rpc_execute flags=0x80 [ 2805.921800] RPC: 1335 call_start nfs3 proc ACCESS (sync) [ 2805.921801] RPC: 1335 call_reserve (status 0) [ 2805.921805] RPC: 1335 reserved req ee8a2900 xid af74741b ** 168 printk messages dropped ** [ 2805.928207] RPC: read reply XID b174741b ** 366 printk messages dropped ** [ 2805.941242] RPC: 1343 setting alarm for 60000 ms ** 310 printk messages dropped ** [ 2805.958274] RPC: xprt = ee240800, tcp_copied = 120, tcp_offset = 120, tcp_reclen = 120 ** 89 printk messages dropped ** [ 2805.959613] RPC: 1350 reserved req ee8a2900 xid be74741b [ 2805.959614] RPC: wake_up_first(ee240918 "xprt_sending") which is just where we want to see the printk messages. This kind'a makes printk and the rpc debug stuff rather useless. :( -- FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
