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From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Trond Myklebust <trondmy@hammerspace.com>
CC:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH v4 2/7] SUNRPC: Avoid NULL pointer dereferences in
 tracepoints
Thread-Topic: [PATCH v4 2/7] SUNRPC: Avoid NULL pointer dereferences in
 tracepoints
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Date:   Wed, 20 Oct 2021 19:39:58 +0000
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> On Oct 20, 2021, at 2:43 PM, Trond Myklebust <trondmy@hammerspace.com> wr=
ote:
>=20
> On Sat, 2021-10-16 at 18:02 -0400, Chuck Lever wrote:
>> On occasion, a NULL rpc_task pointer is passed into tracepoints.
>> We've open-coded a few places where this is expected, but let's
>> be defensive and protect every place that wants to dereference
>> a task to assign the tk_pid and cl_clid.
>>=20
>=20
> No, I won't apply this.
>=20
> This patch is going to lead to a bunch of static checkers complaining
> that we're checking 'task' for NULL after we've already dereferenced it
> in the same function, and/or complaining that we're dereferencing a
> value that might be null because we just had a check for it.

Interesting. I already run "make C=3D1 W=3D1" on every patch. I can update
my development workflow.  Which static checker complains?


> Even within the macros touched by this patch, we have instances of the
> latter occurring, where we read task->tk_client->cl_vers (and other
> fields) immediately after we just declared that we had to check both
> task and task->tk_client for NULL.

Very likely copy-pasta mistakes, but again, my tool chain hadn't
complained.


>> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
>> ---
>>  fs/nfs/nfs4trace.h                 |    8 +---
>>  fs/nfs/nfstrace.h                  |    3 -
>>  include/trace/events/rpcgss.h      |   18 +++-----
>>  include/trace/events/rpcrdma.h     |   62 ++++++++------------------
>> ---
>>  include/trace/events/sunrpc.h      |   77 +++++++++-----------------
>> ----------
>>  include/trace/events/sunrpc_base.h |   15 +++++++
>>  6 files changed, 61 insertions(+), 122 deletions(-)
>>=20
>> diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h
>> index d4f061046c09..66fbd3c33c15 100644
>> --- a/fs/nfs/nfs4trace.h
>> +++ b/fs/nfs/nfs4trace.h
>> @@ -686,10 +686,8 @@ TRACE_EVENT(nfs4_xdr_bad_operation,
>> =20
>>                 TP_fast_assign(
>>                         const struct rpc_rqst *rqstp =3D xdr->rqst;
>> -                       const struct rpc_task *task =3D rqstp->rq_task;
>> =20
>> -                       __entry->task_id =3D task->tk_pid;
>> -                       __entry->client_id =3D task->tk_client-
>>> cl_clid;
>> +                       SUNRPC_TRACE_TASK_ASSIGN(rqstp->rq_task);
>>                         __entry->xid =3D be32_to_cpu(rqstp->rq_xid);
>>                         __entry->op =3D op;
>>                         __entry->expected =3D expected;
>> @@ -721,10 +719,8 @@ DECLARE_EVENT_CLASS(nfs4_xdr_event,
>> =20
>>                 TP_fast_assign(
>>                         const struct rpc_rqst *rqstp =3D xdr->rqst;
>> -                       const struct rpc_task *task =3D rqstp->rq_task;
>> =20
>> -                       __entry->task_id =3D task->tk_pid;
>> -                       __entry->client_id =3D task->tk_client-
>>> cl_clid;
>> +                       SUNRPC_TRACE_TASK_ASSIGN(rqstp->rq_task);
>>                         __entry->xid =3D be32_to_cpu(rqstp->rq_xid);
>>                         __entry->op =3D op;
>>                         __entry->error =3D error;
>> diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
>> index 82b51120450f..e9be65b52bfe 100644
>> --- a/fs/nfs/nfstrace.h
>> +++ b/fs/nfs/nfstrace.h
>> @@ -1401,8 +1401,7 @@ DECLARE_EVENT_CLASS(nfs_xdr_event,
>>                         const struct rpc_rqst *rqstp =3D xdr->rqst;
>>                         const struct rpc_task *task =3D rqstp->rq_task;
>> =20
>> -                       __entry->task_id =3D task->tk_pid;
>> -                       __entry->client_id =3D task->tk_client-
>>> cl_clid;
>> +                       SUNRPC_TRACE_TASK_ASSIGN(task);
>>                         __entry->xid =3D be32_to_cpu(rqstp->rq_xid);
>>                         __entry->version =3D task->tk_client->cl_vers;
>>                         __entry->error =3D error;
>> diff --git a/include/trace/events/rpcgss.h
>> b/include/trace/events/rpcgss.h
>> index 3ba63319af3c..87b17ebd09c3 100644
>> --- a/include/trace/events/rpcgss.h
>> +++ b/include/trace/events/rpcgss.h
>> @@ -96,8 +96,7 @@ DECLARE_EVENT_CLASS(rpcgss_gssapi_event,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->maj_stat =3D maj_stat;
>>         ),
>> =20
>> @@ -330,8 +329,7 @@ TRACE_EVENT(rpcgss_unwrap_failed,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>         ),
>> =20
>>         TP_printk(SUNRPC_TRACE_TASK_SPECIFIER,
>> @@ -355,8 +353,7 @@ TRACE_EVENT(rpcgss_bad_seqno,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->expected =3D expected;
>>                 __entry->received =3D received;
>>         ),
>> @@ -384,8 +381,7 @@ TRACE_EVENT(rpcgss_seqno,
>>         TP_fast_assign(
>>                 const struct rpc_rqst *rqst =3D task->tk_rqstp;
>> =20
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->xid =3D be32_to_cpu(rqst->rq_xid);
>>                 __entry->seqno =3D rqst->rq_seqno;
>>         ),
>> @@ -414,8 +410,7 @@ TRACE_EVENT(rpcgss_need_reencode,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->xid =3D be32_to_cpu(task->tk_rqstp->rq_xid);
>>                 __entry->seq_xmit =3D seq_xmit;
>>                 __entry->seqno =3D task->tk_rqstp->rq_seqno;
>> @@ -448,8 +443,7 @@ TRACE_EVENT(rpcgss_update_slack,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->xid =3D be32_to_cpu(task->tk_rqstp->rq_xid);
>>                 __entry->auth =3D auth;
>>                 __entry->rslack =3D auth->au_rslack;
>> diff --git a/include/trace/events/rpcrdma.h
>> b/include/trace/events/rpcrdma.h
>> index 7f46ef621c95..c2ab9e5d775b 100644
>> --- a/include/trace/events/rpcrdma.h
>> +++ b/include/trace/events/rpcrdma.h
>> @@ -271,8 +271,7 @@ DECLARE_EVENT_CLASS(xprtrdma_rdch_event,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->pos =3D pos;
>>                 __entry->nents =3D mr->mr_nents;
>>                 __entry->handle =3D mr->mr_handle;
>> @@ -320,8 +319,7 @@ DECLARE_EVENT_CLASS(xprtrdma_wrch_event,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->nents =3D mr->mr_nents;
>>                 __entry->handle =3D mr->mr_handle;
>>                 __entry->length =3D mr->mr_length;
>> @@ -380,15 +378,8 @@ DECLARE_EVENT_CLASS(xprtrdma_mr_class,
>>         TP_fast_assign(
>>                 const struct rpcrdma_req *req =3D mr->mr_req;
>> =20
>> -               if (req) {
>> -                       const struct rpc_task *task =3D req-
>>> rl_slot.rq_task;
>> -
>> -                       __entry->task_id =3D task->tk_pid;
>> -                       __entry->client_id =3D task->tk_client-
>>> cl_clid;
>> -               } else {
>> -                       __entry->task_id =3D 0;
>> -                       __entry->client_id =3D -1;
>> -               }
>> +               if (req)
>> +                       SUNRPC_TRACE_TASK_ASSIGN(req-
>>> rl_slot.rq_task);
>>                 __entry->mr_id  =3D mr->mr_ibmr->res.id;
>>                 __entry->nents  =3D mr->mr_nents;
>>                 __entry->handle =3D mr->mr_handle;
>> @@ -633,10 +624,7 @@ TRACE_EVENT(xprtrdma_nomrs_err,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               const struct rpc_rqst *rqst =3D &req->rl_slot;
>> -
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(req->rl_slot.rq_task);
>>                 __assign_str(addr, rpcrdma_addrstr(r_xprt));
>>                 __assign_str(port, rpcrdma_portstr(r_xprt));
>>         ),
>> @@ -694,8 +682,7 @@ TRACE_EVENT(xprtrdma_marshal,
>>         TP_fast_assign(
>>                 const struct rpc_rqst *rqst =3D &req->rl_slot;
>> =20
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->xid =3D be32_to_cpu(rqst->rq_xid);
>>                 __entry->hdrlen =3D req->rl_hdrbuf.len;
>>                 __entry->headlen =3D rqst->rq_snd_buf.head[0].iov_len;
>> @@ -730,8 +717,7 @@ TRACE_EVENT(xprtrdma_marshal_failed,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->xid =3D be32_to_cpu(rqst->rq_xid);
>>                 __entry->ret =3D ret;
>>         ),
>> @@ -757,8 +743,7 @@ TRACE_EVENT(xprtrdma_prepsend_failed,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->xid =3D be32_to_cpu(rqst->rq_xid);
>>                 __entry->ret =3D ret;
>>         ),
>> @@ -791,9 +776,7 @@ TRACE_EVENT(xprtrdma_post_send,
>> =20
>>                 __entry->cq_id =3D sc->sc_cid.ci_queue_id;
>>                 __entry->completion_id =3D sc->sc_cid.ci_completion_id;
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client ?
>> -                                    rqst->rq_task->tk_client-
>>> cl_clid : -1;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->num_sge =3D req->rl_wr.num_sge;
>>                 __entry->signaled =3D req->rl_wr.send_flags &
>> IB_SEND_SIGNALED;
>>         ),
>> @@ -827,9 +810,7 @@ TRACE_EVENT(xprtrdma_post_send_err,
>>                 const struct rpcrdma_ep *ep =3D r_xprt->rx_ep;
>> =20
>>                 __entry->cq_id =3D ep ? ep->re_attr.recv_cq->res.id :
>> 0;
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client ?
>> -                                    rqst->rq_task->tk_client-
>>> cl_clid : -1;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->rc =3D rc;
>>         ),
>> =20
>> @@ -938,10 +919,7 @@ TRACE_EVENT(xprtrdma_post_linv_err,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               const struct rpc_task *task =3D req->rl_slot.rq_task;
>> -
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(req->rl_slot.rq_task);
>>                 __entry->status =3D status;
>>         ),
>> =20
>> @@ -1127,8 +1105,7 @@ TRACE_EVENT(xprtrdma_reply,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->xid =3D be32_to_cpu(rep->rr_xid);
>>                 __entry->credits =3D credits;
>>         ),
>> @@ -1162,8 +1139,7 @@ TRACE_EVENT(xprtrdma_err_vers,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->xid =3D be32_to_cpu(rqst->rq_xid);
>>                 __entry->min =3D be32_to_cpup(min);
>>                 __entry->max =3D be32_to_cpup(max);
>> @@ -1189,8 +1165,7 @@ TRACE_EVENT(xprtrdma_err_chunk,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->xid =3D be32_to_cpu(rqst->rq_xid);
>>         ),
>> =20
>> @@ -1215,8 +1190,7 @@ TRACE_EVENT(xprtrdma_err_unrecognized,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->procedure =3D be32_to_cpup(procedure);
>>         ),
>> =20
>> @@ -1244,8 +1218,7 @@ TRACE_EVENT(xprtrdma_fixup,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->fixup =3D fixup;
>>                 __entry->headlen =3D rqst->rq_rcv_buf.head[0].iov_len;
>>                 __entry->pagelen =3D rqst->rq_rcv_buf.page_len;
>> @@ -1298,8 +1271,7 @@ TRACE_EVENT(xprtrdma_mrs_zap,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>         ),
>> =20
>>         TP_printk(SUNRPC_TRACE_TASK_SPECIFIER,
>> diff --git a/include/trace/events/sunrpc.h
>> b/include/trace/events/sunrpc.h
>> index 92def7d6663e..4fd6299bc907 100644
>> --- a/include/trace/events/sunrpc.h
>> +++ b/include/trace/events/sunrpc.h
>> @@ -69,9 +69,7 @@ DECLARE_EVENT_CLASS(rpc_xdr_buf_class,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client ?
>> -                                    task->tk_client->cl_clid : -1;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->head_base =3D xdr->head[0].iov_base;
>>                 __entry->head_len =3D xdr->head[0].iov_len;
>>                 __entry->tail_base =3D xdr->tail[0].iov_base;
>> @@ -248,8 +246,7 @@ DECLARE_EVENT_CLASS(rpc_task_status,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->status =3D task->tk_status;
>>         ),
>> =20
>> @@ -285,8 +282,7 @@ TRACE_EVENT(rpc_request,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->version =3D task->tk_client->cl_vers;
>>                 __entry->async =3D RPC_IS_ASYNC(task);
>>                 __assign_str(progname, task->tk_client->cl_program-
>>> name);
>> @@ -344,9 +340,7 @@ DECLARE_EVENT_CLASS(rpc_task_running,
>>                 ),
>> =20
>>         TP_fast_assign(
>> -               __entry->client_id =3D task->tk_client ?
>> -                                    task->tk_client->cl_clid : -1;
>> -               __entry->task_id =3D task->tk_pid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->action =3D action;
>>                 __entry->runstate =3D task->tk_runstate;
>>                 __entry->status =3D task->tk_status;
>> @@ -396,9 +390,7 @@ DECLARE_EVENT_CLASS(rpc_task_queued,
>>                 ),
>> =20
>>         TP_fast_assign(
>> -               __entry->client_id =3D task->tk_client ?
>> -                                    task->tk_client->cl_clid : -1;
>> -               __entry->task_id =3D task->tk_pid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->timeout =3D rpc_task_timeout(task);
>>                 __entry->runstate =3D task->tk_runstate;
>>                 __entry->status =3D task->tk_status;
>> @@ -439,8 +431,7 @@ DECLARE_EVENT_CLASS(rpc_failure,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>         ),
>> =20
>>         TP_printk(SUNRPC_TRACE_TASK_SPECIFIER,
>> @@ -476,8 +467,7 @@ DECLARE_EVENT_CLASS(rpc_reply_event,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->xid =3D be32_to_cpu(task->tk_rqstp->rq_xid);
>>                 __assign_str(progname, task->tk_client->cl_program-
>>> name);
>>                 __entry->version =3D task->tk_client->cl_vers;
>> @@ -539,8 +529,7 @@ TRACE_EVENT(rpc_buf_alloc,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->callsize =3D task->tk_rqstp->rq_callsize;
>>                 __entry->recvsize =3D task->tk_rqstp->rq_rcvsize;
>>                 __entry->status =3D status;
>> @@ -570,8 +559,7 @@ TRACE_EVENT(rpc_call_rpcerror,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> -               __entry->task_id =3D task->tk_pid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->tk_status =3D tk_status;
>>                 __entry->rpc_status =3D rpc_status;
>>         ),
>> @@ -606,8 +594,7 @@ TRACE_EVENT(rpc_stats_latency,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> -               __entry->task_id =3D task->tk_pid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->xid =3D be32_to_cpu(task->tk_rqstp->rq_xid);
>>                 __entry->version =3D task->tk_client->cl_vers;
>>                 __assign_str(progname, task->tk_client->cl_program-
>>> name);
>> @@ -655,8 +642,7 @@ TRACE_EVENT(rpc_xdr_overflow,
>>                 if (xdr->rqst) {
>>                         const struct rpc_task *task =3D xdr->rqst-
>>> rq_task;
>> =20
>> -                       __entry->task_id =3D task->tk_pid;
>> -                       __entry->client_id =3D task->tk_client-
>>> cl_clid;
>> +                       SUNRPC_TRACE_TASK_ASSIGN(task);
>>                         __assign_str(progname,
>>                                      task->tk_client->cl_program-
>>> name);
>>                         __entry->version =3D task->tk_client->cl_vers;
>> @@ -721,8 +707,7 @@ TRACE_EVENT(rpc_xdr_alignment,
>>         TP_fast_assign(
>>                 const struct rpc_task *task =3D xdr->rqst->rq_task;
>> =20
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __assign_str(progname,
>>                              task->tk_client->cl_program->name);
>>                 __entry->version =3D task->tk_client->cl_vers;
>> @@ -922,8 +907,7 @@ TRACE_EVENT(rpc_socket_nospace,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->total =3D rqst->rq_slen;
>>                 __entry->remaining =3D rqst->rq_slen - transport-
>>> xmit.offset;
>>         ),
>> @@ -1046,9 +1030,7 @@ TRACE_EVENT(xprt_transmit,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client ?
>> -                       rqst->rq_task->tk_client->cl_clid : -1;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->xid =3D be32_to_cpu(rqst->rq_xid);
>>                 __entry->seqno =3D rqst->rq_seqno;
>>                 __entry->status =3D status;
>> @@ -1082,9 +1064,7 @@ TRACE_EVENT(xprt_retransmit,
>>         TP_fast_assign(
>>                 struct rpc_task *task =3D rqst->rq_task;
>> =20
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client ?
>> -                       task->tk_client->cl_clid : -1;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->xid =3D be32_to_cpu(rqst->rq_xid);
>>                 __entry->ntrans =3D rqst->rq_ntrans;
>>                 __entry->timeout =3D task->tk_timeout;
>> @@ -1137,14 +1117,7 @@ DECLARE_EVENT_CLASS(xprt_writelock_event,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               if (task) {
>> -                       __entry->task_id =3D task->tk_pid;
>> -                       __entry->client_id =3D task->tk_client ?
>> -                                            task->tk_client->cl_clid
>> : -1;
>> -               } else {
>> -                       __entry->task_id =3D -1;
>> -                       __entry->client_id =3D -1;
>> -               }
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->snd_task_id =3D xprt->snd_task ?
>>                                         xprt->snd_task->tk_pid : -1;
>>         ),
>> @@ -1183,14 +1156,7 @@ DECLARE_EVENT_CLASS(xprt_cong_event,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               if (task) {
>> -                       __entry->task_id =3D task->tk_pid;
>> -                       __entry->client_id =3D task->tk_client ?
>> -                                            task->tk_client->cl_clid
>> : -1;
>> -               } else {
>> -                       __entry->task_id =3D -1;
>> -                       __entry->client_id =3D -1;
>> -               }
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->snd_task_id =3D xprt->snd_task ?
>>                                         xprt->snd_task->tk_pid : -1;
>>                 __entry->cong =3D xprt->cong;
>> @@ -1233,8 +1199,7 @@ TRACE_EVENT(xprt_reserve,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D rqst->rq_task->tk_pid;
>> -               __entry->client_id =3D rqst->rq_task->tk_client-
>>> cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(rqst->rq_task);
>>                 __entry->xid =3D be32_to_cpu(rqst->rq_xid);
>>         ),
>> =20
>> @@ -1318,8 +1283,7 @@ TRACE_EVENT(rpcb_getport,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D clnt->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->program =3D clnt->cl_prog;
>>                 __entry->version =3D clnt->cl_vers;
>>                 __entry->protocol =3D task->tk_xprt->prot;
>> @@ -1352,8 +1316,7 @@ TRACE_EVENT(rpcb_setport,
>>         ),
>> =20
>>         TP_fast_assign(
>> -               __entry->task_id =3D task->tk_pid;
>> -               __entry->client_id =3D task->tk_client->cl_clid;
>> +               SUNRPC_TRACE_TASK_ASSIGN(task);
>>                 __entry->status =3D status;
>>                 __entry->port =3D port;
>>         ),
>> diff --git a/include/trace/events/sunrpc_base.h
>> b/include/trace/events/sunrpc_base.h
>> index 588557d07ea8..2cbed4a9a63a 100644
>> --- a/include/trace/events/sunrpc_base.h
>> +++ b/include/trace/events/sunrpc_base.h
>> @@ -10,6 +10,21 @@
>> =20
>>  #include <linux/tracepoint.h>
>> =20
>> +#define SUNRPC_TRACE_PID_SPECIAL       (-1)
>> +
>> +#define SUNRPC_TRACE_TASK_ASSIGN(t) \
>> +       do { \
>> +               if ((t) !=3D NULL) { \
>> +                       __entry->task_id =3D (t)->tk_pid; \
>> +                       __entry->client_id =3D (t)->tk_client ? \
>> +                                            (t)->tk_client->cl_clid
>> : \
>> +                                          =20
>> SUNRPC_TRACE_PID_SPECIAL; \
>> +               } else { \
>> +                       __entry->task_id =3D SUNRPC_TRACE_PID_SPECIAL;
>> \
>> +                       __entry->client_id =3D
>> SUNRPC_TRACE_PID_SPECIAL; \
>> +               } \
>> +       } while (0);
>> +
>>  #define SUNRPC_TRACE_PID_SPECIFIER     "%08x"
>>  #define SUNRPC_TRACE_CLID_SPECIFIER    "%08x"
>>  #define SUNRPC_TRACE_TASK_SPECIFIER \
>>=20
>=20
> --=20
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@hammerspace.com

--
Chuck Lever