RHEL5 : System crashed with "Kernel BUG at fs/dcache.c:612" or "Dentry still in use", RIP shrink_dcache_for_umount_subtree

Issue

• System crash with RIP shrink_dcache_for_umount_subtree or "Dentry still in use (-1)"
• System crashed with following messages:

nfs: server foobar not responding, still trying
nfs: server foobar not responding, still trying
BUG: Dentry ffff8117e1a21660{i=c42927,n=.lsbatch} still in use (-1) [unmount of nfs 0:81]
----------- [cut here ] --------- [please bite here ] ---------
Kernel BUG at fs/dcache.c:612
invalid opcode: 0000 [1] SMP 
last sysfs file: /devices/pci0000:00/0000:00:03.0/0000:01:00.0/0000:02:02.0/0000:0a:00.0/0000:0b:00.0/irq
CPU 0 
Modules linked in: fuse ipmi_si ip6table_filter ip6_tables ebtable_nat ebtables ipt_MASQUERADE iptable_nat ip_nat xt_state ip_conntrack nfnetlink ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables bridge mptctl mptbase dell_rbu nfs nfsd exportfs nfs_acl auth_rpcgss autofs4 ipmi_devintf ipmi_msghandler dm_log_clustered(U) lockd sunrpc be2iscsi ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_addr iscsi_tcp bnx2i cnic ipv6 xfrm_nalgo crypto_api uio cxgb3i libcxgbi iw_cxgb3 ib_core cxgb3 8021q libiscsi_tcp libiscsi2 scsi_transport_iscsi2 scsi_transport_iscsi dm_mirror dm_multipath scsi_dh video backlight sbs power_meter hwmon i2c_ec i2c_core dell_wmi wmi button battery asus_acpi acpi_memhotplug ac parport_pc lp parport ksm(U) kvm(U) joydev ide_cd i7300_edac sr_mod tpm_tis bnx2 tpm edac_mc cdrom sg serio_raw pcspkr tpm_bios dm_raid45 dm_message dm_region_hash dm_log dm_mod dm_mem_cache usb_storage ata_piix libata shpchp megaraid_sas sd_mod scsi_mod ext3 jbd uhci_hcd ohci_hcd ehci_hcd
Pid: 50, comm: events/0 Tainted: G     ---- 2.6.18-308.4.1.el5 #1
RIP: 0010:[<ffffffff800ef567>]  [<ffffffff800ef567>] shrink_dcache_for_umount_subtree+0x177/0x222
..
Process events/0 (pid: 50, threadinfo ffff81203faac000, task ffff81203faa67a0)
..
Call Trace:
 [<ffffffff800efa83>] shrink_dcache_for_umount+0x37/0x45
 [<ffffffff800e774d>] generic_shutdown_super+0x1b/0xfb
 [<ffffffff800e787b>] kill_anon_super+0x9/0x35
 [<ffffffff8873b724>] :nfs:nfs_kill_super+0xd/0x16
 [<ffffffff800e792c>] deactivate_super+0x6a/0x82
 [<ffffffff800f1a44>] release_mounts+0x67/0x89
 [<ffffffff800f1bf2>] expire_mount_list+0x10e/0x162
 [<ffffffff8874372f>] :nfs:nfs_expire_automounts+0x0/0x24
 [<ffffffff800f2c82>] mark_mounts_for_expiry+0x82/0x93
 [<ffffffff88743738>] :nfs:nfs_expire_automounts+0x9/0x24
 [<ffffffff8004d2d2>] run_workqueue+0x9e/0xfb
 [<ffffffff80049ac2>] worker_thread+0x0/0x122
 [<ffffffff80049bb2>] worker_thread+0xf0/0x122
 [<ffffffff8008ee74>] default_wake_function+0x0/0xe
 [<ffffffff80032632>] kthread+0xfe/0x132
 [<ffffffff8005dfb1>] child_rip+0xa/0x11
 [<ffffffff80032534>] kthread+0x0/0x132
 [<ffffffff8005dfa7>] child_rip+0x0/0x11