[PATCH v1 11/14] SUNRPC: Report RPC messages with unknown procedures via a tracepoint

From: Chuck Lever <chuck.lever@oracle.com>
To: bfields@redhat.com
Cc: linux-nfs@vger.kernel.org
Subject: [PATCH v1 11/14] SUNRPC: Report RPC messages with unknown procedures via a tracepoint
Date: Sat, 16 Oct 2021 18:47:30 -0400	[thread overview]
Message-ID: <163442445010.1001.10719088094457400066.stgit@bazille.1015granger.net> (raw)
In-Reply-To: <163442364683.1001.4500967510037013459.stgit@bazille.1015granger.net>

Replace a dprintk call site. The new tracepoint can be left enabled
persistently to capture problems.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/trace/events/sunrpc.h |   30 ++++++++++++++++++++++++++++++
 net/sunrpc/svc.c              |    3 +--
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 804912b26abb..85459c40eb35 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -1716,6 +1716,36 @@ TRACE_EVENT(svc_decode_prog_mismatch_err,
 	)
 );
 
+TRACE_EVENT(svc_decode_proc_unavail_err,
+	TP_PROTO(
+		const struct svc_rqst *rqst,
+		const struct svc_program *progp
+	),
+
+	TP_ARGS(rqst, progp),
+
+	TP_STRUCT__entry(
+		__field(u32, procedure)
+		__field(u32, version)
+		__string(progname, progp->pg_name)
+		__string(addr, rqst->rq_xprt ?
+			 rqst->rq_xprt->xpt_remotebuf : "(null)")
+	),
+
+	TP_fast_assign(
+		__entry->version = rqst->rq_vers;
+		__entry->procedure = rqst->rq_proc;
+		__assign_str(progname, progp->pg_name)
+		__assign_str(addr, rqst->rq_xprt ?
+			     rqst->rq_xprt->xpt_remotebuf : "(null)");
+	),
+
+	TP_printk("addr=%s %sv%u procedure=%u",
+		__get_str(addr), __get_str(progname),
+		__entry->version, __entry->procedure
+	)
+);
+
 DECLARE_EVENT_CLASS(svc_rqst_event,
 
 	TP_PROTO(
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 66e46d7755e9..a0f37e89393f 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1414,8 +1414,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 	goto sendit;
 
 err_bad_proc:
-	svc_printk(rqstp, "unknown procedure (%d)\n", rqstp->rq_proc);
-
+	trace_svc_decode_proc_unavail_err(rqstp, progp);
 	serv->sv_stats->rpcbadfmt++;
 	svc_putnl(resv, RPC_PROC_UNAVAIL);
 	goto sendit;

