Fix: sunrpc: null rpc_clnt dereference in rpc_task_queued tracepoint

Based on upstream Linux commit:

commit 0be283f676a1e7b208db0c992283197ef8b52158
Author: Benjamin Coddington <bcodding@redhat.com>
Date:   Tue Jan 23 09:32:35 2018 -0500

    SUNRPC: Fix null rpc_clnt dereference in rpc_task_queued tracepoint

    Backchannel tasks will not have a reference to the rpc_clnt.  Return -1 for
    cl_clid in that case.

    Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
    Signed-off-by: Trond Myklebust <trondmy@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/instrumentation/events/lttng-module/rpc.h b/instrumentation/events/lttng-module/rpc.h
index fb131060c4fa571e77d7ac0bca192b8e211a7d96..68c622c0c63e09d7192951d3c62d750ee99b42f5 100644 (file)
--- a/instrumentation/events/lttng-module/rpc.h
+++ b/instrumentation/events/lttng-module/rpc.h
@@ -176,7 +176,8 @@ LTTNG_TRACEPOINT_EVENT_CLASS(rpc_task_queued,
 
        TP_FIELDS(
                ctf_integer(unsigned int, task_id, task->tk_pid)
-               ctf_integer(unsigned int, client_id, task->tk_client->cl_clid)
+               ctf_integer(unsigned int, client_id, task->tk_client ?
+                               task->tk_client->cl_clid : -1)
                ctf_integer(unsigned long, timeout, task->tk_timeout)
                ctf_integer(unsigned long, runstate, task->tk_runstate)
                ctf_integer(int, status, task->tk_status)