Multiple nfs clients with the same hostname cause session exceptions,
the new client find confirmed nfs4_client by name in the
nfsd4_create_session
and then will release the se_hash list：

old = find_confirmed_client_by_name(&unconf->cl_name, nn);
if (old) {
    status = mark_client_expired_locked(old);
    if (status) {
        old = NULL;
        goto out_free_conn;
    }
    trace_nfsd_clid_replaced(&old->cl_clientid);
}
move_to_confirmed(unconf);

Is there any other option, such as IP instead of host name, which is
usually unique？

Dec  1 22:42:32 dd kernel: nfsd4_exchange_id rqstp=000000006668b520
exid=00000000a44d3b72 clname.len=35 clname.data=000000007b1b5592
ip_addr=192.168.122.130 flags 101, spa_how 0
Dec  1 22:42:32 dd kernel: nfsd4_exchange_id seqid 0 flags 20001
Dec  1 22:42:32 dd kernel: check_slot_seqid enter. seqid 1 slot_seqid 0
Dec  1 22:42:32 dd kernel: alloc_cld_upcall: allocated xid 10
Dec  1 22:42:32 dd rpc.mountd[25713]: v4.2 client attached:
0xe21bb8c66569eeaf from "192.168.122.130:894"
Dec  1 22:42:32 dd rpc.mountd[25713]: v4.2 client detached:
0xe21bb8c56569eeaf from "192.168.122.93:791"
Dec  1 22:42:32 dd kernel: __find_in_sessionid_hashtbl:
1701441199:3793467590:5:0
Dec  1 22:42:32 dd kernel: nfsd4_sequence: slotid 0
Dec  1 22:42:32 dd kernel: check_slot_seqid enter. seqid 1 slot_seqid 0
Dec  1 22:42:32 dd kernel: nfsd: fh_compose(exp 103:08/128 /, ino=128)
Dec  1 22:42:32 dd kernel: --> nfsd4_store_cache_entry slot 000000006ef6f422
Dec  1 22:42:32 dd kernel: __find_in_sessionid_hashtbl:
1701441199:3793467590:5:0
Dec  1 22:42:32 dd kernel: nfsd4_sequence: slotid 0
Dec  1 22:42:32 dd kernel: check_slot_seqid enter. seqid 2 slot_seqid 1
Dec  1 22:42:32 dd kernel: alloc_cld_upcall: allocated xid 11
Dec  1 22:42:32 dd kernel: --> nfsd4_store_cache_entry slot 000000006ef6f422
Dec  1 22:42:36 dd kernel: __find_in_sessionid_hashtbl:
1701441199:3793467589:4:0
Dec  1 22:42:36 dd kernel: __find_in_sessionid_hashtbl: session not found
Dec  1 22:42:36 dd kernel: nfsd4_destroy_session: 1701441199:3793467589:4:0
Dec  1 22:42:36 dd kernel: __find_in_sessionid_hashtbl:
1701441199:3793467589:4:0
Dec  1 22:42:36 dd kernel: __find_in_sessionid_hashtbl: session not found
Dec  1 22:42:36 dd kernel: nfsd4_exchange_id rqstp=000000006668b520
exid=00000000a44d3b72 clname.len=35 clname.data=000000007b1b5592
ip_addr=192.168.122.93 flags 101, spa_how 0
Dec  1 22:42:36 dd kernel: nfsd4_exchange_id seqid 0 flags 20001
Dec  1 22:42:36 dd kernel: check_slot_seqid enter. seqid 1 slot_seqid 0
Dec  1 22:42:36 dd kernel: alloc_cld_upcall: allocated xid 12
Dec  1 22:42:36 dd rpc.mountd[25713]: v4.2 client attached:
0xe21bb8c76569eeaf from "192.168.122.93:791"
Dec  1 22:42:36 dd rpc.mountd[25713]: v4.2 client detached:
0xe21bb8c66569eeaf from "192.168.122.130:894"
Dec  1 22:42:36 dd kernel: __find_in_sessionid_hashtbl:
1701441199:3793467591:6:0
Dec  1 22:42:36 dd kernel: nfsd4_sequence: slotid 0
Dec  1 22:42:36 dd kernel: check_slot_seqid enter. seqid 1 slot_seqid 0
Dec  1 22:42:36 dd kernel: nfsd: fh_compose(exp 103:08/128 /, ino=128)
Dec  1 22:42:36 dd kernel: --> nfsd4_store_cache_entry slot 00000000e1f66c24
Dec  1 22:42:36 dd kernel: __find_in_sessionid_hashtbl:
1701441199:3793467591:6:0
Dec  1 22:42:36 dd kernel: nfsd4_sequence: slotid 0
Dec  1 22:42:36 dd kernel: check_slot_seqid enter. seqid 2 slot_seqid 1
Dec  1 22:42:36 dd kernel: alloc_cld_upcall: allocated xid 13
Dec  1 22:42:36 dd kernel: --> nfsd4_store_cache_entry slot 00000000e1f66c24
Dec  1 22:43:33 dd kernel: __find_in_sessionid_hashtbl:
1701441199:3793467590:5:0
Dec  1 22:43:33 dd kernel: __find_in_sessionid_hashtbl: session not found
Dec  1 22:43:33 dd kernel: nfsd4_destroy_session: 1701441199:3793467590:5:0
Dec  1 22:43:33 dd kernel: __find_in_sessionid_hashtbl:
1701441199:3793467590:5:0
Dec  1 22:43:33 dd kernel: __find_in_sessionid_hashtbl: session not found