System panicked in free_block()

Issue

System panicked with this message:

Unable to handle kernel NULL pointer dereference at 0000000000000000 RIP: 
 [<ffffffff800e0272>] free_block+0x6f/0x145
PGD 2bcc477067 PUD 2be627e067 PMD 0 
Oops: 0000 [1] SMP 
last sysfs file: /devices/pci0000:00/0000:00:00.0/irq
CPU 31 
Modules linked in: tcp_diag inet_diag ipmi_devintf ipmi_si ipmi_msghandler mptctl mptbase oracleasm(U) bonding be2iscsi iscsi_tcp bnx2i cnic uio cxgb3i libcxgbi cxgb3 libiscsi_tcp libiscsi2 scsi_transport_iscsi2 scsi_transport_iscsi rdma_ucm(U) rds_tcp(U) rds_rdma(U) rds(U) ib_ucm(U) rdma_cm(U) iw_cm(U) ib_addr(U) ib_ipoib(U) ib_cm(U) ib_sa(U) ipoib_helper(U) ipv6 xfrm_nalgo crypto_api ib_uverbs(U) ib_umad(U) iw_nes(U) mlx4_ib(U) ib_mthca(U) ib_mad(U) ib_core(U) emcpvlumd(PU) emcpxcrypt(PU) emcpdm(PU) emcpgpx(PU) emcpmpx(PU) emcp(PU) dm_mirror dm_log dm_multipath scsi_dh dm_mod video backlight sbs power_meter hwmon i2c_ec i2c_core dell_wmi wmi button battery asus_acpi acpi_memhotplug ac parport_pc lp parport joydev mlx4_en(U) sg mlx4_core(U) tpm_tis hpilo tpm pcspkr serio_raw be2net(U) tpm_bios i7core_edac edac_mc 8021q lpfc(U) scsi_transport_fc shpchp cciss sd_mod scsi_mod ext3 jbd uhci_hcd ohci_hcd ehci_hcd
Pid: 225, comm: events/31 Tainted: P     ---- 2.6.18-348.1.1.el5 #1
RIP: 0010:[<ffffffff800e0272>]  [<ffffffff800e0272>] free_block+0x6f/0x145
RSP: 0000:ffff81303fa3dd80  EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff81403fc81418 RCX: 00000000000fe000
RDX: 000001bc80000000 RSI: 0000000000000000 RDI: ffff813040019080
RBP: 0000000000000018 R08: 0000000000000003 R09: 000000000e5885d0
R10: ffff81203f55c860 R11: 0000000000000008 R12: ffff813040019080
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff81403fcd2940(0000) knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000000000000000 CR3: 0000002c96d45000 CR4: 00000000000006a0
Process events/31 (pid: 225, threadinfo ffff81303fa3c000, task ffff81203f55c860)
Stack:  ffff813031d4dac0 0000001800000000 ffff81403fc81418 ffff81403fc81418
 0000000000000018 ffff81403fc81400 0000000000000003 ffff81304001a140
 ffff813040019080 ffffffff800e03d3 ffff81203f55c860 0000000000000000
Call Trace:
 [<ffffffff800e03d3>] drain_array+0x8b/0xc0
 [<ffffffff800e0e14>] cache_reap+0x0/0x217
 [<ffffffff800e0eb9>] cache_reap+0xa5/0x217
 [<ffffffff8004d8b9>] run_workqueue+0x9e/0xfb
 [<ffffffff8004a102>] worker_thread+0x0/0x122
 [<ffffffff8004a1f2>] worker_thread+0xf0/0x122
 [<ffffffff8008f38d>] default_wake_function+0x0/0xe
 [<ffffffff80032c2c>] kthread+0xfe/0x132
 [<ffffffff8005dfc1>] child_rip+0xa/0x11
 [<ffffffff80032b2e>] kthread+0x0/0x132
 [<ffffffff8005dfb7>] child_rip+0x0/0x11

Code: 48 8b 06 48 83 e0 fc 48 8d 14 10 48 8b 02 25 00 40 02 00 48 
RIP  [<ffffffff800e0272>] free_block+0x6f/0x145
 RSP <ffff81303fa3dd80>