linux-kernel - Re: nfs problems with 2.6.18-rc1

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 17 Jul 2006 09:23:38 +1000
From:	Neil Brown <neilb@...e.de>
To:	Janos Farkas <chexum+dev@...il.com>
Cc:	linux-kernel@...r.kernel.org, nfs@...ts.sourceforge.net
Subject: Re: nfs problems with 2.6.18-rc1

On Thursday July 13, chexum+dev@...il.com wrote:
> Hi!
> 
> I recently updated two (old) hosts to 2.6.18-rc1, and started noticing
> weird things with the nfs mounted /home s.

So this is both the client and the server that you upgraded?  That
makes is harder to point the finger of blame :-)

> 
> I frequently face EACCESs where a few minutes ago there wasn't any
> problem, and after a retry everything does work again.
> 

I wonder if that is pointing the finger at

http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=8c7b389e532e964f07057dac8a56c43465544759

as that is a recent change that returns 'EACCES'... but I cannot see
that being relevant in this case as it only affects directories.

> 
> How can I help with tracing this?  git bisecting on these machines takes
> at least an hour per step, (and no reasonable connectivity either to
> compile elsewhere much quicker).

The standard answer for tracing nfs problems if 'tcpdump'.
e.g. 
  tcpdump -s 0 -w /tmp/trace host $CLIENT and host $SERVER and port 2049

that should show whether the error is coming from the server, or if
the client is generating it all by itself.
If you can get a reasonably small '/tmp/trace', compress it and attach
it to an email.

Also turn on tracing. Something like:
on server
   echo 32767 > /proc/sys/sunrpc/nfsd_debug
on client
   echo 32767 > /proc/sys/sunrpc/nfs_debug

You can be a bit more selective by only enabling individual flags.
For the server, these are in include/linux/nfsd/debug.h
You probably want FH, EXPORT AUTH PROC FILEOP

For the client, they are near the end of include/linux/nfs_fs.h
Not sure which to choose... maybe just all of them.

NeilBrown
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/