NFS hangs in 2.4.27

NFS hangs in 2.4.27

[Christoph Pleger]

Hello,

Since a few days I have great NFS problems on six Linux machines. The
execution of "ps aux" shows that processes are hanging for they are
waiting for the completion of uninterruptable NFS I/O and the system
utilization becomes very high.

The hangs occurred since the installation of Kernel 2.4.27 (used 2.4.26
before), so I guess that Kernel 2.4.27 introduces the problems with NFS.
I am not sure about that, but since I reinstalled the old 2.4.26-Kernel
on one of the six computers, that machine works fine.

Has someone else experienced NFS hangs under 2.4.27 so far?

Kind regards
  Christoph Pleger

Re: NFS hangs in 2.4.27

[Willy Tarreau]

On Wed, Sep 08, 2004 at 02:07:30PM +0200, Christoph Pleger wrote:
> Hello,
> 
> Since a few days I have great NFS problems on six Linux machines. The
> execution of "ps aux" shows that processes are hanging for they are
> waiting for the completion of uninterruptable NFS I/O and the system
> utilization becomes very high.
> 
> The hangs occurred since the installation of Kernel 2.4.27 (used 2.4.26
> before), so I guess that Kernel 2.4.27 introduces the problems with NFS.
> I am not sure about that, but since I reinstalled the old 2.4.26-Kernel
> on one of the six computers, that machine works fine.
> 
> Has someone else experienced NFS hangs under 2.4.27 so far?

I have seen this only with the preempt patch applied and enabled. But since
the kernel also had lots of other patches applied, I cannot tell that it is
only NFS+preemt alone. It deadlocked on a spinlock() in nfs_sync_page() IIRC.

But no problem so far with preempt disabled.

Regards,
Willy