Kernel panic in kfree() function.

Issue

• Server rebooted on its own and need to determine the reason for the same.
• Kernel panic in kfree() function:

Unable to handle kernel paging request at ffff89a4563fe740 RIP: 
 [<ffffffff8020b7ed>] kfree+0x4f/0xc5
PGD 0 
Oops: 0000 [1] SMP 
last sysfs file: /class/fc_remote_ports/rport-6:0-0/roles
CPU 0 
Modules linked in: joydev xt_physdev lock_dlm gfs2 dlm configfs netloop netbk blktap blkbk ipt_MASQUERADE iptable_nat ip_nat xt_state ip_conntrack nfnetlink ipt_REJECT xt_tcpudp iptable_filter ip_tables x_tables mptctl mptbase bridge ipv6 xfrm_nalgo crypto_api ipmi_devintf ipmi_si ipmi_msghandler bonding dm_round_robin dm_multipath scsi_dh video hwmon backlight sbs i2c_ec button battery asus_acpi ac parport_pc lp parport st sr_mod cdrom sg pcspkr i2c_i801 i2c_core bnx2(U) usb_storage cdc_ether usbnet dm_raid45 dm_message dm_region_hash dm_mem_cache dm_snapshot dm_zero dm_mirror dm_log dm_mod qla2xxx scsi_transport_fc ata_piix libata shpchp megaraid_sas(U) sd_mod scsi_mod ext3 jbd uhci_hcd ohci_hcd ehci_hcd
Pid: 3, comm: ksoftirqd/0 Tainted: G      2.6.18-128.4.1.el5xen #1
RIP: e030:[<ffffffff8020b7ed>]  [<ffffffff8020b7ed>] kfree+0x4f/0xc5
RSP: e02b:ffffffff8066af08  EFLAGS: 00010082
RAX: 000001a454b2e740 RBX: ffff8800331d83d8 RCX: 0000000000000000
RDX: ffff89a4563fe740 RSI: ffff8800331d8150 RDI: 00000018331d848c
RBP: 00000018331d848c R08: ffff880001481818 R09: 0000000000000000
R10: ffff880076ad7300 R11: ffff8800010ade80 R12: 0000000000000000
R13: 0000000000000009 R14: 0000000000000000 R15: 0000000000000000
FS:  00002af24b601560(0000) GS:ffffffff805ba000(0000) knlGS:0000000000000000
CS:  e033 DS: 0000 ES: 0000
Process ksoftirqd/0 (pid: 3, threadinfo ffff880007fc6000, task ffff8800000227e0)
Stack:  ffff8800331d83d8  ffff8800331d8860  0000000000000005  ffffffff8025d782 
 ffff8800010add80  ffffffff8029803c  ffff8800010ade80  0000000000000001 
 0000000000000000  ffffffff802980e5 
Call Trace:
 <IRQ>  [<ffffffff8025d782>] d_callback+0x1a/0x2a
 [<ffffffff8029803c>] __rcu_process_callbacks+0x12b/0x1b1
 [<ffffffff802980e5>] rcu_process_callbacks+0x23/0x43
 [<ffffffff8028e507>] tasklet_action+0x91/0x10d
 [<ffffffff80212872>] __do_softirq+0x8d/0x13b
 [<ffffffff8025fda4>] call_softirq+0x1c/0x278
 <EOI>  [<ffffffff8028e3b7>] ksoftirqd+0x0/0xbf
 [<ffffffff8026d08e>] do_softirq+0x31/0x98
 [<ffffffff8028e416>] ksoftirqd+0x5f/0xbf
 [<ffffffff80233575>] kthread+0xfe/0x132
 [<ffffffff8025fb2c>] child_rip+0xa/0x12
 [<ffffffff80233477>] kthread+0x0/0x132
 [<ffffffff8025fb22>] child_rip+0x0/0x12

Code: 48 8b 02 25 00 40 02 00 48 3d 00 40 02 00 75 04 48 8b 52 10 
RIP  [<ffffffff8020b7ed>] kfree+0x4f/0xc5
 RSP <ffffffff8066af08>