From 823c73d0c539a0c1740c7929a7aad3f844e69d70 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 19 Jul 2021 10:48:10 -0400 Subject: SUNRPC: Unset RPC_TASK_NO_RETRANS_TIMEOUT for NULL RPCs In some rare failure modes, the server is actually reading the transport, but then just dropping the requests on the floor. TCP_USER_TIMEOUT cannot detect that case. Prevent such a stuck server from pinning client resources indefinitely by ensuring that certain idempotent requests (such as NULL) can time out even if the connection is still operational. Otherwise rpc_bind_new_program(), gss_destroy_cred(), or rpc_clnt_test_and_add_xprt() can wait forever. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker --- net/sunrpc/clnt.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index ca2000d8cf64..d34737a8a68a 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -2694,6 +2694,18 @@ static const struct rpc_procinfo rpcproc_null = { .p_decode = rpcproc_decode_null, }; +static void +rpc_null_call_prepare(struct rpc_task *task, void *data) +{ + task->tk_flags &= ~RPC_TASK_NO_RETRANS_TIMEOUT; + rpc_call_start(task); +} + +static const struct rpc_call_ops rpc_null_ops = { + .rpc_call_prepare = rpc_null_call_prepare, + .rpc_call_done = rpc_default_callback, +}; + static struct rpc_task *rpc_call_null_helper(struct rpc_clnt *clnt, struct rpc_xprt *xprt, struct rpc_cred *cred, int flags, @@ -2707,7 +2719,7 @@ struct rpc_task *rpc_call_null_helper(struct rpc_clnt *clnt, .rpc_xprt = xprt, .rpc_message = &msg, .rpc_op_cred = cred, - .callback_ops = (ops != NULL) ? ops : &rpc_default_ops, + .callback_ops = ops ?: &rpc_null_ops, .callback_data = data, .flags = flags | RPC_TASK_SOFT | RPC_TASK_SOFTCONN | RPC_TASK_NULLCREDS, @@ -2758,6 +2770,7 @@ static void rpc_cb_add_xprt_release(void *calldata) } static const struct rpc_call_ops rpc_cb_add_xprt_call_ops = { + .rpc_call_prepare = rpc_null_call_prepare, .rpc_call_done = rpc_cb_add_xprt_done, .rpc_release = rpc_cb_add_xprt_release, }; -- cgit v1.2.3-58-ga151