Re: [PATCH 0/3] NFS regression in 2.6.26?, "task blocked for more than 120 seconds"

Kasparek Tomas
2009-03-03T12:08:55Z

On Tue, Jan 20, 2009 at 10:32:27AM -0500, Trond Myklebust wrote:
> > > > > > The attached 2 patches have been tested using a server that was rigged
> > > > > > not to ever close the socket. They appear to work fine on my setup,
> > > > > > without the hang that you reported earlier.
> > > ...
> > > It seems that machines with this new kernel (tried on 10 other machines
> > > and the original client) may after few days get into state where they
> > > generate huge amounts (10000-100000pkt/s) of packets on another server they
> > > use (Linux 2.6.26.62, but the same behaviour with other kernels I tried -
> > > 2.6.24.7, 2.6.22.19, 2.6.27.10). It seems packets are quiet small as the
> > > flow on server is about 5-10MB/s. (probably) Each packet generates an answer.
> > > With this flow it is hard to get more info and the server is production
> > > one, so for now I only know it goes from these clients and end on tcp port
> > > 2049 on that server. It kills just this server, communication with the
> > > previously problematic (FreeBSD machines) is fine now.

> > configrming that the problem is with machines with 2.6.27.10+trond's
> > patches. Do not have more info about what's there on network, the only new
> > thing I can add is that the client is dead not reacting even on keyborad or
> > anything else. Trond, would you have and idea what to try now or what other
> > information to find to get any further in this?
>
> A binary wireshark dump of the traffic between one such client and the
> server would help.

I was able to finally got the tcpdump. I got it from 2.6.27.19 client but
after several weeks without problems. I include the file and place it on
http://merlin.fit.vutbr.cz/tmp/nfs/dump_kas2_mat.dump_small (have over 1GB
of dump, but it's all the time the same SYN+RST packets). The packet rate
maxed at 260000pps from two clients.

This dump is taken from server after reset (the server does not respond
even to keybord) before clients are disconnected/rebooted. To remind it - all
clients seems to work well with reversed
e06799f958bf7f9f8fae15f0c6f519953fb0257c

(just to be a hint do not mean the patch is wrong)

Thanks in advance

--

Tomas Kasparek, PhD student E-mail: kasparek@fit.vutbr.cz
CVT FIT VUT Brno, L127 Web: http://www.fit.vutbr.cz/~kasparek
Bozetechova 1, 612 66 Fax: +420 54114-1270
Brno, Czech Republic Phone: +420 54114-1220

jabber: tomas.kasparek@jabber.cz
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