Re: WARNING at fs/nfs/write.c:743 nfs_inode_remove_request with -rc6

Weston Andros Adamson
2014-09-23T14:59:28Z

On Sep 23, 2014, at 10:53 AM, Will Deacon <will.deacon@arm.com> wrote:

> On Tue, Sep 23, 2014 at 02:59:38PM +0100, Will Deacon wrote:
>> On Tue, Sep 23, 2014 at 02:33:06PM +0100, Weston Andros Adamson wrote:
>>> Any more info on how to reproduce this would be really great. Unfortunately I don’t
>>> have access to an arm64 system.
>>
>> I've not spotted a pattern other than using 64k pages, yet. If I manage to
>> get a reproducer, I'll let you know.
>>
>>> If it’s possible, could we get a packet trace around when this happens? This is pure
>>> speculation, but this might have something to do the resend path - a commit fails
>>> and all the requests on the commit list have to be resent.
>>
>> Sure, once I can reproduce it reliably, then I'll try to do that.
>
> Right, a bunch of DDing from /dev/zero over an ssh session triggers this
> very quickly. I've put a binary tcpdump here:
>
> http://www.willdeacon.ukfsn.org/bitbucket/oopsen/nfs/tcpdump.bin
>
> You may want to filter out the ssh packets. The only `interesting' thing to
> me is a retransmission about half way through, but I don't know what I'm
> looking for.
>
> The NFS server is 10.1.203.204 and the client is 10.1.203.24.

Thanks! You are using NFSv2, so there are no commits - that rules out my hunch.

-dros