Problem with mount.nfs4 on latest Fedora 10 updates

[Howard Wilkinson]

Chuck Lever wrote:
>
> On Aug 13, 2009, at 12:50 PM, Howard Wilkinson wrote:
>
>> I have just upgraded a couple of servers from FC9 to FC10 and I am 
>> seeing a major problem with mount.nfs4. This occurs when autofs calls 
>> the mount program. It then runs at 100% CPU and never terminates.
>>
>> I have VMs that are running similar configuration successfully, so 
>> this is something driven by being on bare metal.
>>
>> Kernel is 2.6.27.29-170.2.78.fc10.i686.PAE
>> nfs-utils is nfs-utils-1.1.4-8.fc10.i386
>> autofs is autofs-5.0.3-41.i386
>>
>> Command running is
>>
>> /sbin/mount.nfs4 battleaxe:/ /hosts/battleaxe -s -o 
>> rw,nosuid,nodev,tcp,rsize=32768,wsize=32768,hard,intr
>>
>> The autofs mount has worked and the directories under 
>> /hosts/battleaxe have been successfully accessed prior to the problem 
>> occuring - I suspect this is a remount after and expire has occurred.
>>
>> Anybody seen this before?
>> Anybody know what I can do to get round this? [I am on the way to 
>> FC11 but will have to live with FC10 for a while (a week or so)]
>> Any extra information I can acquire to diagnose this?
>>
>> There is nothing in the log files to indicate anything going wrong, I 
>> could turn debug on if I knew what to set and which messages to strip 
>> once I do.
>
> You could start with "sudo rpcdebug -m nfs -s mount" and look in 
> /var/log/messages, or you can strace the running mount command.
>
> -- 
> Chuck Lever
> chuck[dot]lever[at]oracle[dot]com
The mount.nfs4 involvement is a red-herring! It would seem that the 
problem is in the kernel - probably in the NFS4 code path. I have now 
seem bash, df, and cfagent all exhibit the same failure. The processes 
go to 100% and hang up probably in a kernel thread. This happens some 
time after the kernel has booted so may still involve something to do 
with the autofs timing out the mount.

If I revert the kernel (and nothing else) to the latest FC9 version then 
everything goes back to working as it was.

Does anybody recognise these symptoms?

I am going to see if an strace will work, but once the system has failed 
it is difficult to get other processes to run to completion.

Howard.