lockd silently dies (goes defunct)

lockd is going defunct after an undetermined period of time in gutsy server. Please advise as to troubleshooting next steps.

Various system information:

# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Genuine Intel(R) CPU 2160 @ 1.80GHz
stepping : 2
cpu MHz : 1795.592
cache size : 1024 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 2
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pni monitor ds_cpl est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 3593.27
clflush size : 64

processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Genuine Intel(R) CPU 2160 @ 1.80GHz
stepping : 2
cpu MHz : 1795.592
cache size : 1024 KB
physical id : 0
siblings : 2
core id : 1
cpu cores : 2
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pni monitor ds_cpl est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 3591.07
clflush size : 64

# free
             total used free shared buffers cached
Mem: 3069464 820604 2248860 0 824 668960
-/+ buffers/cache: 150820 2918644
Swap: 1951888 0 1951888

# lspci
00:00.0 Host bridge: Intel Corporation 82Q35 Express DRAM Controller (rev 02)
00:02.0 VGA compatible controller: Intel Corporation 82Q35 Express Integrated Graphics Controller (rev 02)
00:02.1 Display controller: Intel Corporation 82Q35 Express Integrated Graphics Controller (rev 02)
00:03.0 Communication controller: Intel Corporation 82Q35 Express MEI Controller (rev 02)
00:19.0 Ethernet controller: Intel Corporation 82566DM-2 Gigabit Network Connection (rev 02)
00:1a.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 02)
00:1a.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 02)
00:1a.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 02)
00:1a.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 02)
00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 02)
00:1c.1 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 2 (rev 02)
00:1c.2 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 3 (rev 02)
00:1c.3 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 4 (rev 02)
00:1c.4 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 5 (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 02)
00:1d.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 92)
00:1f.0 ISA bridge: Intel Corporation LPC Interface Controller (rev 02)
00:1f.2 SATA controller: Intel Corporation 82801IR/IO/IH (ICH9R/DO/DH) 6 port SATA AHCI Controller (rev 02)
00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller (rev 02)
03:00.0 IDE interface: Marvell Technology Group Ltd. 88SE6101 single-port PATA133 interface (rev b1)
06:00.0 Ethernet controller: Intel Corporation 82540EM Gigabit Ethernet Controller (rev 02)
06:03.0 FireWire (IEEE 1394): Agere Systems FW323 (rev 70)

# lsmod
Module Size Used by
nfsd 220656 13
exportfs 6912 1 nfsd
lockd 67592 2 nfsd
sunrpc 172284 9 nfsd,lockd
xt_TCPMSS 5888 1
xt_tcpmss 3200 1
iptable_mangle 3840 1
pppoe 15680 2
pppox 4872 1 pppoe
xt_tcpudp 4224 6
ipt_MASQUERADE 4608 1
xt_state 3456 5
iptable_nat 8708 1
nf_conntrack_ipv4 19724 6 iptable_nat
iptable_filter 3968 1
ip_tables 13924 3 iptable_mangle,iptable_nat,iptable_filter
x_tables 16260 7 xt_TCPMSS,xt_tcpmss,xt_tcpudp,ipt_MASQUERADE,xt_state,iptable_nat,ip_tables
nf_nat_irc 3712 0
nf_conntrack_irc 8088 1 nf_nat_irc
nf_nat_ftp 4352 0
nf_nat 20012 4 ipt_MASQUERADE,iptable_nat,nf_nat_irc,nf_nat_ftp
nf_conntrack_ftp 11136 1 nf_nat_ftp
nf_conntrack 65160 9 ipt_MASQUERADE,xt_state,iptable_nat,nf_conntrack_ipv4,nf_nat_irc,nf_conntrack_irc,nf_nat_ftp,nf_nat,nf_conntrack_ftp
nfnetlink 6936 3 nf_conntrack_ipv4,nf_nat,nf_conntrack
af_packet 24840 4
ppp_generic 29332 6 pppoe,pppox
slhc 7552 1 ppp_generic
ext3 133640 1
jbd 60456 1 ext3
mbcache 9732 1 ext3
sbp2 24584 0
lp 12452 0
parport 37448 1 lp
loop 19076 0
snd_hda_intel 263712 0
snd_pcm_oss 44544 0
snd_mixer_oss 17664 1 snd_pcm_oss
snd_pcm 80388 2 snd_hda_intel,snd_pcm_oss
snd_seq_dummy 4740 0
snd_seq_oss 33152 0
snd_seq_midi 9600 0
snd_rawmidi 25728 1 snd_seq_midi
snd_seq_midi_event 8448 2 snd_seq_oss,snd_seq_midi
snd_seq 53104 6 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_seq_midi_event
snd_timer 24324 2 snd_pcm,snd_seq
snd_seq_device 9228 5 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_rawmidi,snd_seq
snd 54532 9 snd_hda_intel,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_seq_device
soundcore 8800 1 snd
psmouse 39952 0
intel_agp 25620 1
snd_page_alloc 11528 2 snd_hda_intel,snd_pcm
shpchp 34580 0
pci_hotplug 32576 1 shpchp
agpgart 35144 1 intel_agp
ipv6 278916 42
serio_raw 8068 0
joydev 11328 0
evdev 11136 0
pcspkr 4224 0
e1000_ich9 189376 0
heci 60044 0
xfs 573528 2
sr_mod 17700 0
cdrom 37408 1 sr_mod
usbhid 29664 0
hid 28928 1 usbhid
sg 36380 0
sd_mod 30336 8
pata_marvell 8064 3
ohci1394 36784 0
ieee1394 96312 2 sbp2,ohci1394
e1000 126656 0
ahci 23428 2
ata_generic 8580 0
libata 125168 3 pata_marvell,ahci,ata_generic
scsi_mod 146828 5 sbp2,sr_mod,sg,sd_mod,libata
ehci_hcd 36748 0
uhci_hcd 26640 0
usbcore 138760 4 usbhid,ehci_hcd,uhci_hcd
raid10 26496 0
raid456 128272 0
xor 16904 1 raid456
raid1 25856 1
raid0 9728 0
multipath 9984 0
linear 7552 0
md_mod 82324 8 raid10,raid456,raid1,raid0,multipath,linear
thermal 14344 0
processor 32072 1 thermal
fan 5764 0
fuse 47124 1
apparmor 40600 0
commoncap 8320 1 apparmor

# exportfs -v
/home 10.0.0.9(rw,async,wdelay,root_squash)