[PATCH 5.9 124/252] SUNRPC: Fix oops in the rpc_xdr_buf event class

[Greg Kroah-Hartman]

From: Scott Mayhew <smayhew@xxxxxxxxxx>

[ Upstream commit c3213d260a23e263ef85ba21ac68c9e7578020b5 ]

Backchannel rpc tasks don't have task->tk_client set, so it's necessary
to check it for NULL before dereferencing.

Fixes: c509f15a5801 ("SUNRPC: Split the xdr_buf event class")
Signed-off-by: Scott Mayhew <smayhew@xxxxxxxxxx>
Reviewed-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 include/trace/events/sunrpc.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index ca2f27b9f919d..1652cc32aebcd 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -68,7 +68,8 @@ DECLARE_EVENT_CLASS(rpc_xdr_buf_class,
 
 	TP_fast_assign(
 		__entry->task_id = task->tk_pid;
-		__entry->client_id = task->tk_client->cl_clid;
+		__entry->client_id = task->tk_client ?
+				     task->tk_client->cl_clid : -1;
 		__entry->head_base = xdr->head[0].iov_base;
 		__entry->head_len = xdr->head[0].iov_len;
 		__entry->tail_base = xdr->tail[0].iov_base;
-- 
2.27.0