Kernel panic in megasas_complete_cmd_dpc() function.

Issue

• Kernel oops while the application was issuing ioctl to the device of MagaRAID.
• Kernel panic with following call traces in Red Hat Enterprise Linux 4.

Unable to handle kernel NULL pointer dereference at 0000000000000008 RIP: 
<ffffffffa008bdfd>{:megaraid_sas:megasas_complete_cmd_dpc+152}
PML4 11dab8067 PGD 1927ec067 PMD 0 
Oops: 0000 [1] SMP 
CPU 3 
Modules linked in: nls_utf8 nfsd exportfs mptctl md5 ipv6 autofs4 i2c_dev i2c_core ipmi(U) smbus(U) nfs lockd nfs_acl sunrpc iptable_filter joydev ds yenta_socket pcmcia_core ipt_MASQUERADE iptable_nat ip_conntrack ip_tables ide_dump scsi_dump diskdump zlib_deflate dm_mirror usb_storage button battery ac uhci_hcd ehci_hcd hw_random igb inet_lro sr_mod sg ext3 jbd dm_mod mptscsih mptspi megaraid_sas mptsas mptscsi mptbase ata_piix libata sd_mod scsi_mod
Pid: 4343, comm: reconstructPar Not tainted 2.6.9-89.ELlargesmp
RIP: 0010:[<ffffffffa008bdfd>] <ffffffffa008bdfd>{:megaraid_sas:megasas_complete_cmd_dpc+152}
RSP: 0000:0000010037e97ee8  EFLAGS: 00010046
RAX: 0000000000000003 RBX: 0000010000051800 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000102374392b8
RBP: 0000010037dd4980 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000000000d R12: 0000010237439248
R13: 00000000000001d9 R14: 00000000000001da R15: 0000000000000246
FS:  0000002a989cd940(0000) GS:ffffffff80517500(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 0000000438f90000 CR4: 00000000000006e0
Process reconstructPar (pid: 4343, threadinfo 000001008d45e000, task 0000010336910030)
Stack: 0000000000000000 0000010237439380 0000000000000000 000000000000000a 
       0000000000000003 000001008d45ff58 0000007fbfffaae0 ffffffff8013d944 
       ffffffff80517500 0000000000000001 
Call Trace:<IRQ> <ffffffff8013d944>{tasklet_action+103} <ffffffff8013d5e4>{__do_softirq+88} 
        <ffffffff8013d68d>{do_softirq+49} <ffffffff801132f3>{do_IRQ+328} 
        <ffffffff801108c3>{ret_from_intr+0}  <EOI> 
Code: 48 8b 42 08 83 b8 88 00 00 00 01 77 2a 80 7b 02 00 75 24 80 
 RIP <ffffffffa008bdfd>{:megaraid_sas:megasas_complete_cmd_dpc+152} RSP <0000010037e97ee8>
 CR2: 0000000000000008

• Kernel panic with following call traces in Red Hat Enterprise Linux 5.

BUG: unable to handle kernel NULL pointer dereference at virtual address 00000110
printing eip:
f8901de8
*pde = 36fbc001
Oops: 0002 [#1]
SMP 
last sysfs file: /devices/pci0000:ff/0000:ff:00.0/irq
Modules linked in: mptctl mptbase autofs4 hidp ipmi(U) smbus(U) rfcomm l2cap bluetooth sunrpc cpufreq_ondemand acpi_cpufreq dm_multipath scsi_dh dm_mod video hwmon backlight sbs i2c_ec button battery asus_acpi ac ipv6 xfrm_nalgo crypto_api parport_pc lp parport joydev sr_mod cdrom sg i2c_i801 i2c_core igb pcspkr ata_piix libata megaraid_sas sd_mod scsi_mod ext3 jbd uhci_hcd ohci_hcd ehci_hcd
CPU:    3
EIP:    0060:[<f8901de8>]    Tainted: G      VLI
EFLAGS: 00010046   (2.6.18-128.el5PAE #1) 
EIP is at megasas_complete_cmd_dpc+0xba/0x2e4 [megaraid_sas]
eax: 00000000   ebx: f7687c00   ecx: cda7a2e0   edx: cda7a204
esi: 00000001   edi: 00000000   ebp: f796d700   esp: c0735fb4
ds: 007b   es: 007b   ss: 0068
Process swapper (pid: 0, ti=c0735000 task=cd966aa0 task.ti=cd967000)
Stack: 000001b6 000001b5 cda7a2e0 00000286 cda7a39c 00000001 00000000 0000000a 
       c0429113 cd967f38 00000001 c06e4b28 c042900f 00000003 cd967f38 cd967000 
       00000046 000000b1 c04073d7 
Call Trace:
   [<c0429113>] tasklet_action+0x77/0xf0
   [<c042900f>] __do_softirq+0x87/0x114
   [<c04073d7>] do_softirq+0x52/0x9c
   [<c044b060>] __do_IRQ+0x0/0xd6
   [<c04074d6>] do_IRQ+0xb5/0xc3
   [<c0405946>] common_interrupt+0x1a/0x20
   [<c051007b>] acpi_ex_convert_to_target_type+0x11/0xd2
   [<c0525592>] acpi_processor_idle+0x166/0x394
   [<c0403ca8>] cpu_idle+0x9f/0xb9
   =======================
Code: 18 74 37 77 11 84 c0 74 1f 3c 0c 0f 85 9a 00 00 00 e9 86 00 00 00 3c 2e 74 20 3c 33 74 7e 3c 2d 0f 85 85 00 00 00 eb 26 8b 45 28 <c7> 80 10 01 00 00 00 00 00 00 e9 8f 00 00 00 0f b6 43 03 8b 55 
  EIP: [<f8901de8>] megasas_complete_cmd_dpc+0xba/0x2e4 [megaraid_sas] SS:ESP 0068:c0735fb4