Why Panic at show_map with process wscanuse ?

Issue

The server had a panic and got self rebooted with following panic string.

 vgptool[14681]: [UnixLogger:NOTICE] [NOTICE 7/16/2012 18:01:32 controller.cpp:354] VGP Apply Policy - CallType: REFRESH 
 kernel: Unable to handle kernel NULL pointer dereference at virtual address 000001b8
 kernel:  printing eip:
 kernel: c018548c
 kernel: *pde = 27034001
 kernel: Oops: 0000 [#1]
 kernel: SMP 
 kernel: Modules linked in: nfs lockd nfs_acl md5 ipv6 autofs4 sunrpc dm_mirror button battery ac ohci_hcd tg3 ext3 jbd dm_mod
 kernel: CPU:    0
 kernel: EIP:    0060:[<c018548c>]    Not tainted VLI
 kernel: EFLAGS: 00010246   (2.6.9-34.ELsmp) 
 kernel: EIP is at show_map+0x70/0x111
 kernel: eax: 00000000   ebx: f67af5f4   ecx: 00000003   edx: f4df77b0
 kernel: esi: 00100073   edi: e775e480   ebp: f52e9d80   esp: e6a41f24
 kernel: ds: 007b   es: 007b   ss: 0068
 kernel: Process wscanuse (pid: 31112, threadinfo=e6a41000 task=f492d330)
 kernel: Stack: 00000070 00125000 00000003 00000002 00070045 e6a41f40 f4df77b0 c032c980 
 kernel:        c032c980 e775e480 00000000 f67af5f4 c0174680 00000203 00000000 00000400 
 kernel:        b778c000 00000008 00000000 00000007 00000000 c032ce60 f5fa3880 00000400 
 kernel: Call Trace:
 kernel:  [<c0174680>] seq_read+0x1c7/0x2c2
 kernel:  [<c015a43d>] vfs_read+0xb6/0xe2
 kernel:  [<c015a650>] sys_read+0x3c/0x62
 kernel:  [<c02d2657>] syscall_call+0x7/0xb
 kernel:  [<c02d007b>] schedule+0x32f/0x8d3
 kernel: Code: c1 e0 0c 50 89 f0 24 80 3c 01 19 c0 83 e0 fd 83 c0 73 f7 c6 04 00 00 00 50 75 1b 83 3d bc 11 41 c0 00 75 19 8b 54 24 18 8b 42 70 <8b> 80 b8 01 00 00 39 43 04 73 07 b8 78 00 00 00 eb 05 b8 2d 00 
 kernel:  <0>Fatal exception: panic in 5 seconds
 syslogd 1.4.1: restart.
 syslog: syslogd startup succeeded
 kernel: klogd 1.4.1, log source = /proc/kmsg started.
 kernel: Linux version 2.6.9-34.ELsmp (<a class="make_room_for_kcs" href="mailto:bhcompile@hs20-bc1-7.build.redhat.com">bhcompile@hs20-bc1-7.build.redhat.com</a>) (gcc version 3.4.5 20051201 (Red Hat 3.4.5-2)) #1 SMP Fri Feb 24 16:54:53 EST 2006