From: Andrew Morton <akpm@linux-foundation.org>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Subject: Re: net-2.6.22 UDP stalls/hangs
Date: Mon, 23 Apr 2007 15:37:14 -0700 [thread overview]
Message-ID: <20070423153714.71b9d99e.akpm@linux-foundation.org> (raw)
In-Reply-To: <20070423.151531.70219647.davem@davemloft.net>
On Mon, 23 Apr 2007 15:15:31 -0700 (PDT)
David Miller <davem@davemloft.net> wrote:
> From: Andrew Morton <akpm@linux-foundation.org>
> Date: Mon, 23 Apr 2007 15:12:40 -0700
>
> > which is just stupid. The rtnl_lock() is right there in ip_mc_join_group().
> > And this is a different architecture and config and compiler from yesterday's
> > fun. And no scheduler patches involved here.
>
> Perhaps something on another cpu is dropping the rtnl semaphore one
> times too many.
>
> Recently a bug of this nature was discovered in the wireless stack.
> But unless you have a wireless device in this box too, it's probably
> unrelated.
Could be. But I'd expect the mutex code to whine about the extra unlock.
And about from an unlock from a different thread. If I have that option
turned on.
Oh well, one thing at a time. The good news is that I can reproduce the
problem with netperf.
kpm:/usr/src/netperf-2.4.3> netperf -H akpm2 -t UDP_RR
UDP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to akpm2 (172.18.116.155) port 0 AF_INET
netperf: receive_response: no response received. errno 0 counter 0
That's running netserver on the test machine.
The machine running netperf is 172.18.116.160 and the test machine running
netserver is 172.18.116.155
tcpdump from the test machine:
15:24:37.924210 802.1d config 8000.00:18:74:5d:04:66.80ae root 0066.00:15:c7:20:57:c0 pathcost 4 age 1 max 20 hello 2 fdelay 15
15:24:38.859309 IP 172.18.119.252.hsrp > 224.0.0.2.hsrp: HSRPv0-hello 20: state=standby group=1 addr=172.18.119.254
15:24:39.078273 IP 172.18.119.253.hsrp > 224.0.0.2.hsrp: HSRPv0-hello 20: state=active group=1 addr=172.18.119.254
15:24:39.924074 802.1d config 8000.00:18:74:5d:04:66.80ae root 0066.00:15:c7:20:57:c0 pathcost 4 age 1 max 20 hello 2 fdelay 15
15:24:40.017081 IP 172.24.0.7.domain > 172.18.116.57.37456: 59635 4/7/6 CNAME[|domain]
15:24:41.383433 IP 172.18.116.160.33137 > 172.18.116.155.12865: S 2760291763:2760291763(0) win 5840 <mss 1460,sackOK,timestamp 1967355840 0,nop,wscale 8>
15:24:41.383479 IP 172.18.116.155.12865 > 172.18.116.160.33137: S 1640262480:1640262480(0) ack 2760291764 win 5792 <mss 1460,sackOK,timestamp 7714 1967355840,nop,wscale 7>
15:24:41.383683 IP 172.18.116.160.33137 > 172.18.116.155.12865: . ack 1 win 23 <nop,nop,timestamp 1967355840 7714>
15:24:41.383883 IP 172.18.116.160.33137 > 172.18.116.155.12865: P 1:257(256) ack 1 win 23 <nop,nop,timestamp 1967355840 7714>
15:24:41.383902 IP 172.18.116.155.12865 > 172.18.116.160.33137: . ack 257 win 54 <nop,nop,timestamp 7714 1967355840>
15:24:41.384065 IP 172.18.116.155.12865 > 172.18.116.160.33137: P 1:257(256) ack 257 win 54 <nop,nop,timestamp 7714 1967355840>
15:24:41.587266 IP 172.18.116.155.12865 > 172.18.116.160.33137: P 1:257(256) ack 257 win 54 <nop,nop,timestamp 7765 1967355840>
15:24:41.839234 IP 172.18.119.252.hsrp > 224.0.0.2.hsrp: HSRPv0-hello 20: state=standby group=1 addr=172.18.119.254
15:24:41.924303 802.1d config 8000.00:18:74:5d:04:66.80ae root 0066.00:15:c7:20:57:c0 pathcost 4 age 1 max 20 hello 2 fdelay 15
15:24:41.995285 IP 172.18.116.155.12865 > 172.18.116.160.33137: P 1:257(256) ack 257 win 54 <nop,nop,timestamp 7867 1967355840>
15:24:42.030341 IP 172.18.119.253.hsrp > 224.0.0.2.hsrp: HSRPv0-hello 20: state=active group=1 addr=172.18.119.254
15:24:42.811330 IP 172.18.116.155.12865 > 172.18.116.160.33137: P 1:257(256) ack 257 win 54 <nop,nop,timestamp 8071 1967355840>
15:24:43.924183 802.1d config 8000.00:18:74:5d:04:66.80ae root 0066.00:15:c7:20:57:c0 pathcost 4 age 1 max 20 hello 2 fdelay 15
15:24:44.121880 IP 172.24.0.7.domain > 172.18.116.22.46700: 52073* 1/4/4 A[|domain]
15:24:44.443419 IP 172.18.116.155.12865 > 172.18.116.160.33137: P 1:257(256) ack 257 win 54 <nop,nop,timestamp 8479 1967355840>
15:24:44.723257 IP 172.18.119.252.hsrp > 224.0.0.2.hsrp: HSRPv0-hello 20: state=standby group=1 addr=172.18.119.254
15:24:44.886356 IP 172.18.119.253.hsrp > 224.0.0.2.hsrp: HSRPv0-hello 20: state=active group=1 addr=172.18.119.254
15:24:45.924263 802.1d config 8000.00:18:74:5d:04:66.80ae root 0066.00:15:c7:20:57:c0 pathcost 4 age 1 max 20 hello 2 fdelay 15
15:24:47.659300 IP 172.18.119.252.hsrp > 224.0.0.2.hsrp: HSRPv0-hello 20: state=standby group=1 addr=172.18.119.254
15:24:47.707599 IP 172.18.116.155.12865 > 172.18.116.160.33137: P 1:257(256) ack 257 win 54 <nop,nop,timestamp 9295 1967355840>
15:24:47.874419 IP 172.18.119.253.hsrp > 224.0.0.2.hsrp: HSRPv0-hello 20: state=active group=1 addr=172.18.119.254
15:24:47.952350 802.1d config 8000.00:18:74:5d:04:66.80ae root 0066.00:15:c7:20:57:c0 pathcost 4 age 1 max 20 hello 2 fdelay 15
15:24:48.037569 IP 172.24.0.7.domain > 172.18.117.18.46665: 59092 2/7/6 CNAME[|domain]
So I think we did a bit of TCP chatter then no UDP at all?
It's interesting that the test machine can see other people's DNS queries
go past.
next prev parent reply other threads:[~2007-04-23 22:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-23 20:07 net-2.6.22 UDP stalls/hangs Andrew Morton
2007-04-23 20:18 ` David Miller
2007-04-23 20:27 ` Andrew Morton
2007-04-23 20:37 ` David Miller
2007-04-23 20:56 ` Andrew Morton
2007-04-23 21:17 ` David Miller
2007-04-23 21:45 ` Andrew Morton
2007-04-23 22:12 ` Andrew Morton
2007-04-23 22:15 ` David Miller
2007-04-23 22:37 ` Andrew Morton [this message]
2007-04-23 22:45 ` David Miller
2007-04-23 23:35 ` Andrew Morton
2007-04-24 0:04 ` Herbert Xu
2007-04-24 0:07 ` David Miller
2007-04-23 23:14 ` Rick Jones
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