linux-kernel - Re: NFSROOT with NFS Version 3

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

Message-Id: <20061120120750.1b1688e8.Christoph.Pleger@uni-dortmund.de>
Date:	Mon, 20 Nov 2006 12:07:50 +0100
From:	Christoph Pleger <Christoph.Pleger@...-dortmund.de>
To:	linux-kernel@...r.kernel.org
Subject: Re: NFSROOT with NFS Version 3

Hello,

On Fri, 17 Nov 2006 11:20:17 -0500
Trond Myklebust <trond.myklebust@....uio.no> wrote:

> On Fri, 2006-11-17 at 16:40 +0100, Christoph Pleger wrote:
> > Hello,
> > 
> > I tried to switch an NFSROOT-Environment from NFS version 2 to NFS
> > version 3, but unfortunately my test client machine now hangs every
> > time after booting as soon as some bigger file system activity
> > should occur. I tried Kernel 2.6.14.7 and Kernel 2.6.16.32.
> > 
> > The problem did not occur with NFS version 2.
> > 
> > Does anybody know the problem and/or a solution?
> 
> That is almost always due to the difference in r/wsize that the Linux
> NFS server advertises for v2 and v3 combined with using UDP. If you
> have poor networking, then don't use UDP, and certainly not with 32k
> r/wsize.
> 
> IOW: try either setting the mount options "rsize=8192,wsize=8192", or
> the option "proto=tcp"

No, that was not the problem. I tried it, bit it did not help.

Later, I noticed the following message that appeared during the boot
process:

Warning: Unable to open an initial console

So, on the NFS server, I made a copy of the NFSROOT-Directory, exported
the copy read-write (the original is exported read-only) and used the
copy as NFSROOT for the client. And now the client works well.

But now I have two questions:

1. Why did the problem not occur with NFS version 2? On the client,
/dev/console should have been read-only with version 2 as well.
2. What can I do to get a "real" solution? Exporting the original
NFSROOT read-write is not possible for me.

Regards
  Christoph Pleger
-
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/