rpciod process is getting hung in Red Hat Enterprise Linux 5

Issue

• Any access on the NFSv4 mount is getting hung
• Following messages are seen on the client side.

kernel: INFO: task rpciod/6:833 blocked for more than 120 seconds.
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: rpciod/6      D ffff8102eb520050     0   833    307           834   832 (L-TLB)
kernel:  ffff81087ce75c40 0000000000000046 0000000000000006 ffffffff800fb1de
kernel:  ffff8102f1ab02f0 000000000000000a ffff81087de7d7e0 ffff81087c612820
kernel:  000e2aa8f01d9b39 000000000000098e ffff81087de7d9c8 0000000600000001
kernel: Call Trace:
kernel:  [<ffffffff800fb1de>] ep_poll_callback+0x64/0x8b
kernel:  [<ffffffff8002e283>] __wake_up+0x38/0x4f
kernel:  [<ffffffff880be996>] :nfs:nfs_idmap_id+0x189/0x209
kernel:  [<ffffffff8008e40a>] default_wake_function+0x0/0xe
kernel:  [<ffffffff880b97fc>] :nfs:decode_getfattr+0x73c/0xc5e
kernel:  [<ffffffff880ba9b4>] :nfs:nfs4_xdr_dec_write+0x0/0xbd
kernel:  [<ffffffff8803dca0>] :sunrpc:rpc_async_schedule+0x0/0x5
kernel:  [<ffffffff880baa67>] :nfs:nfs4_xdr_dec_write+0xb3/0xbd
kernel:  [<ffffffff8803890d>] :sunrpc:call_decode+0x4b7/0x509
kernel:  [<ffffffff8803dae4>] :sunrpc:__rpc_execute+0x92/0x24e
kernel:  [<ffffffff8004d7d0>] run_workqueue+0x99/0xf6
kernel:  [<ffffffff8004a018>] worker_thread+0x0/0x122
kernel:  [<ffffffff800a269c>] keventd_create_kthread+0x0/0xc4
kernel:  [<ffffffff8004a108>] worker_thread+0xf0/0x122
kernel:  [<ffffffff8008e40a>] default_wake_function+0x0/0xe
kernel:  [<ffffffff800a269c>] keventd_create_kthread+0x0/0xc4
kernel:  [<ffffffff800a269c>] keventd_create_kthread+0x0/0xc4
kernel:  [<ffffffff80032996>] kthread+0xfe/0x132
kernel:  [<ffffffff8005dfb1>] child_rip+0xa/0x11
kernel:  [<ffffffff800a269c>] keventd_create_kthread+0x0/0xc4
kernel:  [<ffffffff80032898>] kthread+0x0/0x132
kernel:  [<ffffffff8005dfa7>] child_rip+0x0/0x11

• NFS diskless systems are getting hung.