[RHEL5] iptables restart fails and service hangs on "unloading module".

• iptables restart fails and service hangs on "unloading module" with below messages:.

kernel: INFO: task iptables-restor:29402 blocked for more than 120 seconds.
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: iptables-rest D ffffffff80151248 0 29402 29395 (NOTLB)
kernel: ffff810215721ad8 0000000000000082 00002b210a61d000 ffff81010d9a5540
kernel: 00000000000000e8 0000000000000001 ffff810214a2a820 ffff81012fe46100
kernel: 000692d32449e45c 000000000016fa74 ffff810214a2aa08 0000000b00000000
kernel: Call Trace:
kernel: [<ffffffff80064167>] wait_for_completion+0x79/0xa2
kernel: [<ffffffff8008e16d>] default_wake_function+0x0/0xe
kernel: [<ffffffff8009e566>] call_usermodehelper_keys+0xe3/0xf8
kernel: [<ffffffff8009e57b>] __call_usermodehelper+0x0/0x4f
kernel: [<ffffffff8009e953>] request_module+0x139/0x14d
kernel: [<ffffffff88050065>] :ext3:ext3_journalled_write_end+0x10/0x13d
kernel: [<ffffffff800c8dc6>] __rmqueue+0x91/0xc6
kernel: [<ffffffff800cd378>] zone_statistics+0x3e/0x6d
kernel: [<ffffffff80001c20>] _stext+0xc20/0x1000
kernel: [<ffffffff80064ae3>] mutex_lock_interruptible+0x9/0x1e
kernel: [<ffffffff88322f4a>] :x_tables:xt_find_match+0xbc/0xca
kernel: [<ffffffff883312e0>] :ip_tables:translate_table+0x1d5/0x66e
kernel: [<ffffffff8833256f>] :ip_tables:do_ipt_set_ctl+0xfe/0x256
kernel: [<ffffffff80248446>] nf_sockopt+0xce/0x10c
kernel: [<ffffffff802484a5>] nf_setsockopt+0x16/0x18
kernel: [<ffffffff80250fee>] ip_setsockopt+0x61/0x78
kernel: [<ffffffff80226d9c>] sys_setsockopt+0x91/0xb7
kernel: [<ffffffff8005e28d>] tracesys+0xd5/0xe0
kernel:
kernel: INFO: task modprobe:29477 blocked for more than 120 seconds.
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: modprobe D ffffffff80151248 0 29477 29451 (NOTLB)
kernel: ffff8100ceab9ed8 0000000000000082 0000000000000296 ffffffff804a16f0
kernel: ffffffff804a16f8 0000000000000001 ffff8100ccd11820 ffff81012fe46100
kernel: 000692e662dd6f03 0000000000000b72 ffff8100ccd11a08 0000000b800640cb
kernel: Call Trace:
kernel: [<ffffffff8006410d>] wait_for_completion+0x1f/0xa2
kernel: [<ffffffff802484ec>] nf_unregister_sockopt+0x45/0x5c
kernel: [<ffffffff88332b90>] :ip_tables:ip_tables_fini+0x10/0x3f
kernel: [<ffffffff800a77fb>] sys_delete_module+0x196/0x1c5
kernel: [<ffffffff8005e28d>] tracesys+0xd5/0xe0