Sadly, after a bit more testing I find that 4.20.10 with that patch applied still exhibits the problem. Just found a machine where NFS hung up just six minutes after the user logged in. As always: nothing is logged to the client or the server. I turned on the tracing as requested previously and see what I think it just the same sequence as before. Please let me know if there is any other information I can provide. Right now I'm going to build 4.20.10 with my previously posted revert patch applied and roll that out to the same 50 hosts and see how it fares. - J< kworker/u8:0-12608 [001] .... 47884.661073: rpc_request: task:20469@1 nfsv4 SEQUENCE (async) kworker/u8:0-12608 [001] .... 47884.661073: rpc_task_run_action: task:20469@1 flags=5281 state=0005 status=0 action=call_reserve [sunrpc] kworker/u8:0-12608 [001] .... 47884.661074: rpc_task_run_action: task:20469@1 flags=5281 state=0005 status=0 action=call_reserveresult [sunrpc] kworker/u8:0-12608 [001] .... 47884.661074: rpc_task_run_action: task:20469@1 flags=5281 state=0005 status=0 action=call_refresh [sunrpc] kworker/u8:0-12608 [001] .... 47884.661075: rpc_task_run_action: task:20469@1 flags=5281 state=0005 status=0 action=call_refreshresult [sunrpc] kworker/u8:0-12608 [001] .... 47884.661076: rpc_task_run_action: task:20469@1 flags=5281 state=0005 status=0 action=call_allocate [sunrpc] kworker/u8:0-12608 [001] .... 47884.661076: rpc_task_run_action: task:20469@1 flags=5281 state=0005 status=0 action=call_encode [sunrpc] kworker/u8:0-12608 [001] .... 47884.661091: rpc_task_run_action: task:20469@1 flags=5281 state=001d status=0 action=call_bind [sunrpc] kworker/u8:0-12608 [001] .... 47884.661091: rpc_task_run_action: task:20469@1 flags=5281 state=001d status=0 action=call_connect [sunrpc] kworker/u8:0-12608 [001] .... 47884.661092: rpc_task_run_action: task:20469@1 flags=5281 state=001d status=0 action=call_transmit [sunrpc] kworker/u8:0-12608 [001] .... 47884.661106: xprt_transmit: peer=[172.21.86.74]:2049 xid=0x0d7ca068 status=0 kworker/u8:0-12608 [001] .... 47884.661107: rpc_task_run_action: task:20469@1 flags=5a81 state=0015 status=0 action=call_transmit_status [sunrpc] kworker/u8:0-12608 [001] .... 47884.661107: rpc_task_sleep: task:20469@1 flags=5a81 state=0015 status=0 timeout=60000 queue=xprt_pending kworker/u9:0-12884 [002] .... 47884.661371: xprt_lookup_rqst: peer=[172.21.86.74]:2049 xid=0x0d7ca068 status=0 kworker/u9:0-12884 [002] .... 47884.661372: xprt_complete_rqst: peer=[172.21.86.74]:2049 xid=0x0d7ca068 status=112 kworker/u9:0-12884 [002] .... 47884.661373: rpc_task_wakeup: task:20469@1 flags=5a81 state=0006 status=0 timeout=60000 queue=xprt_pending kworker/u9:0-12884 [002] .... 47884.661375: xs_stream_read_request: peer=[172.21.86.74]:2049 xid=0x0d7ca068 copied=112 reclen=112 offset=112 kworker/u9:0-12884 [002] .... 47884.661376: xs_stream_read_data: peer=[172.21.86.74]:2049 err=-11 total=116 kworker/u8:0-12608 [001] .... 47884.661388: rpc_task_run_action: task:20469@1 flags=5a81 state=0005 status=0 action=xprt_timer [sunrpc] kworker/u8:0-12608 [001] .... 47884.661389: rpc_task_run_action: task:20469@1 flags=5a81 state=0005 status=0 action=call_status [sunrpc] kworker/u8:0-12608 [001] .... 47884.661389: rpc_task_run_action: task:20469@1 flags=5a81 state=0005 status=0 action=call_decode [sunrpc] kworker/u8:0-12608 [001] .... 47884.661408: rpc_task_run_action: task:20469@1 flags=5a81 state=0005 status=-10063 action=rpc_exit_task [sunrpc] kworker/u8:0-12608 [001] .... 47884.661409: nfs4_sequence_done: error=-10063 (SEQ_MISORDERED) session=0x4480e725 slot_nr=0 seq_nr=1 highest_slotid=0 target_highest_slotid=0 status_flags=0 () kworker/u8:0-12608 [001] .... 47884.661410: rpc_stats_latency: task:20469@1 xid=0x0d7ca068 nfsv4 SEQUENCE backlog=21 rtt=278 execute=339 kworker/u8:0-12608 [001] .... 47884.661412: rpc_task_run_action: task:20469@1 flags=5281 state=0005 status=0 action=rpc_prepare_task [sunrpc] kworker/u8:0-12608 [001] .... 47884.661413: nfs4_setup_sequence: session=0x4480e725 slot_nr=0 seq_nr=1 highest_used_slotid=0 kworker/u8:0-12608 [001] .... 47884.661413: rpc_task_run_action: task:20469@1 flags=5281 state=0005 status=0 action=call_start [sunrpc] kworker/u8:0-12608 [001] .... 47884.661414: rpc_request: task:20469@1 nfsv4 SEQUENCE (async)