SUNRPC: Fix general protection fault in trace_rpc_xdr_overflow()

[ Upstream commit d321ff589c16d8c2207485a6d7fbdb14e873d46e ]

The TP_fast_assign() section is careful enough not to dereference
xdr->rqst if it's NULL. The TP_STRUCT__entry section is not.

Fixes: 5582863f450c ("SUNRPC: Add XDR overflow trace event")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index 65d7dfbbc9cd7d04e5a68bf09a79ec09a338af76..ca2f27b9f919da02715c9de03a73e9d8c46ddfdc 100644 (file)
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -607,10 +607,10 @@ TRACE_EVENT(rpc_xdr_overflow,
                __field(size_t, tail_len)
                __field(unsigned int, page_len)
                __field(unsigned int, len)
-               __string(progname,
-                        xdr->rqst->rq_task->tk_client->cl_program->name)
-               __string(procedure,
-                        xdr->rqst->rq_task->tk_msg.rpc_proc->p_name)
+               __string(progname, xdr->rqst ?
+                        xdr->rqst->rq_task->tk_client->cl_program->name : "unknown")
+               __string(procedure, xdr->rqst ?
+                        xdr->rqst->rq_task->tk_msg.rpc_proc->p_name : "unknown")
        ),
 
        TP_fast_assign(