Subject: Re: [PATCH 2/3] svcrdma: handle rdma read with a non-zero initial
 page offset
To: trond.myklebust@primarydata.com, bfields@fieldses.org
References: <20150921172423.9761.92399.stgit@build2.ogc.int>
 <20150921172428.9761.27838.stgit@build2.ogc.int>
Cc: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org
From: Steve Wise <swise@opengridcomputing.com>
Message-ID: <56094F3D.2030002@opengridcomputing.com>
Date: Mon, 28 Sep 2015 09:31:25 -0500
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Sender: linux-nfs-owner@vger.kernel.org

On 9/21/2015 12:24 PM, Steve Wise wrote:
> The server rdma_read_chunk_lcl() and rdma_read_chunk_frmr() functions
> were not taking into account the initial page_offset when determining
> the rdma read length.  This resulted in a read who's starting address
> and length exceeded the base/bounds of the frmr.
>
> Most work loads don't tickle this bug apparently, but one test hit it
> every time: building the linux kernel on a 16 core node with 'make -j
> 16 O=/mnt/0' where /mnt/0 is a ramdisk mounted via NFSRDMA.
>
> This bug seems to only be tripped with devices having small fastreg page
> list depths.  I didn't see it with mlx4, for instance.
>
> Fixes: 0bf4828983df ('svcrdma: refactor marshalling logic')
> Signed-off-by: Steve Wise <swise@opengridcomputing.com>
> Tested-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>
>

Hey Bruce, can this make 4.3-rc?  Also, what do you think about pushing 
it to stable?

Thanks,

Steve.