> On Nov 30, 2018, at 5:18 PM, Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote:
>
> On Fri, 2018-11-30 at 17:15 -0500, Chuck Lever wrote:
>>> On Nov 30, 2018, at 4:55 PM, Trond Myklebust <trondmy@xxxxxxxxx>
>>> wrote:
>>>
>>> A call to gss_wrap_req_priv() will end up replacing the original
>>> array
>>> in rqstp->rq_snd_buf.pages with a new one containing the encrypted
>>> data. In order to avoid having the rqstp->rq_snd_buf.bvec point to
>>> the
>>> wrong page data, we need to refresh that too.
>>
>> I would add a note here that this patch fixes a memory leak. And
>> you might want to add a Fixes: tag.
>>
>
> It only applies to new code that went into 4.20, so it won't need any
> stable backporting.
>
> That said, I'm realising (slowly - apparently I'm asleep today) that
> this is receive side code, so
>
> a) The contents of rq_snd_buf are irrelevant.
> b) We want to beware of changing it while there is a copy in
> rq_private_buf.
>
> IOW: a v4 is forthcoming.
fwiw, i see the soft IRQ warnings with NFS/RDMA too.
I would like to turn those into a pr_warn_rate_limited. I don't
see much point in the backtrace blather.
>> I'm trying it out now.
>>
>>
>>> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>>> ---
>>> include/linux/sunrpc/xdr.h | 1 -
>>> net/sunrpc/xprt.c | 2 ++
>>> net/sunrpc/xprtsock.c | 1 +
>>> 3 files changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/include/linux/sunrpc/xdr.h
>>> b/include/linux/sunrpc/xdr.h
>>> index 43106ffa6788..2ec128060239 100644
>>> --- a/include/linux/sunrpc/xdr.h
>>> +++ b/include/linux/sunrpc/xdr.h
>>> @@ -72,7 +72,6 @@ xdr_buf_init(struct xdr_buf *buf, void *start,
>>> size_t len)
>>> buf->head[0].iov_base = start;
>>> buf->head[0].iov_len = len;
>>> buf->tail[0].iov_len = 0;
>>> - buf->bvec = NULL;
>>> buf->pages = NULL;
>>> buf->page_len = 0;
>>> buf->flags = 0;
>>> diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
>>> index 86bea4520c4d..122c91c28e7c 100644
>>> --- a/net/sunrpc/xprt.c
>>> +++ b/net/sunrpc/xprt.c
>>> @@ -1623,6 +1623,8 @@ xprt_request_init(struct rpc_task *task)
>>> req->rq_snd_buf.buflen = 0;
>>> req->rq_rcv_buf.len = 0;
>>> req->rq_rcv_buf.buflen = 0;
>>> + req->rq_snd_buf.bvec = NULL;
>>> + req->rq_rcv_buf.bvec = NULL;
>>> req->rq_release_snd_buf = NULL;
>>> xprt_reset_majortimeo(req);
>>> dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid,
>>> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
>>> index ae77c71c1f64..615ef2397fc5 100644
>>> --- a/net/sunrpc/xprtsock.c
>>> +++ b/net/sunrpc/xprtsock.c
>>> @@ -843,6 +843,7 @@ static int xs_nospace(struct rpc_rqst *req)
>>> static void
>>> xs_stream_prepare_request(struct rpc_rqst *req)
>>> {
>>> + xdr_free_bvec(&req->rq_rcv_buf);
>>> req->rq_task->tk_status = xdr_alloc_bvec(&req->rq_rcv_buf,
>>> GFP_NOIO);
>>> }
>>>
>>> --
>>> 2.19.2
>>>
>>
>> --
>> Chuck Lever
>>
>>
>>
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@xxxxxxxxxxxxxxx
--
Chuck Lever
