Kernel bug or hardware problem

Atmel 9G20 based custom board with 32MB SDRAM.  Experiencing "random"
segmentation faults.  The following is an example,

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c1edc000
[00000000] *pgd=21ddc031, *pte=00000000, *ppte=00000000
Internal error: Oops: 817 [#1]
Modules linked in:
CPU: 0    Not tainted  (2.6.27.4 #4)
PC is at __bug+0x20/0x2c
LR is at check_preempt_wakeup+0x118/0x130
pc : [<c002dc38>]    lr : [<c003ca3c>]    psr: 60000093
sp : c1eb7ba8  ip : c0356690  fp : c1eb7bb4
r10: 00000032  r9 : 00000050  r8 : c1cd53c0
r7 : c1cf03f0  r6 : c1caa000  r5 : c1cf03e0  r4 : c1cf03e8
r3 : 00000000  r2 : 60000093  r1 : 00000001  r0 : 00000021
Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 0005317f  Table: 21edc000  DAC: 00000015
Process wget (pid: 476, stack limit = 0xc1eb6268)
Stack: (0xc1eb7ba8 to 0xc1eb8000)
7ba0:                   c1eb7bf4 c1eb7bb8 c0080be8 c002dc28 c00a5cc4 00000050
7bc0: 00000050 00000000 00000000 40000013 00000000 c1cd53c0 00000050 c0377c7c
7be0: 00001000 c18523c8 c1eb7c14 c1eb7bf8 c0080a80 c0080ac8 c1859710 00000000
7c00: c0377c78 c03573d0 c1eb7c3c c1eb7c18 c00da3cc c0080a40 c1859710 c1859710
7c20: c1859710 c18523c8 c1dd45c0 00000000 c1eb7c64 c1eb7c40 c00d7338 c00da3a0
7c40: c18540e8 c1859710 c1859710 c18523c8 000002a9 00000000 c1eb7c8c c1eb7c68
7c60: c00c8314 c00d7308 c00c8e7c 000002a9 01fa2000 c1859710 00001000 c1859710
7c80: c1eb7cbc c1eb7c90 c00c7498 c00c8308 c1eb7d04 000002a9 000002a9 01fa2000
7ca0: 00000000 c18540e8 c1cdece0 c0398b40 c1eb7d04 c1eb7cc0 c00ca078 c00c7430
7cc0: 00000000 c00c82f8 00000000 c1eb6000 c1854180 c18523c8 000002a9 000002a9
7ce0: 000002a9 01fa2000 00000000 c1eb6000 c1eb7d50 00000000 c1eb7d94 c1eb7d08
7d00: c0065818 c00ca000 000002a9 000002a9 c0398b40 c0097ddc c1854180 c1eb7e90
7d20: c1cdece0 c1854180 c02a2884 c18540e8 000002f7 00001000 00000000 c02a2884
7d40: 00000241 0989298b c009b454 c1eb7d68 c1eb7f20 00000001 000002f7 000002a9
7d60: c0097ddc c0398b40 00000241 c1854154 c18540e8 01fa1d09 00000000 c18540e8
7d80: 00000000 000005a0 c1eb7e1c c1eb7d98 c0066318 c0065698 01fa1d09 00000000
7da0: c1eb7ee0 000005a0 00000000 c1eb6000 c0374a68 c1eb7ee0 c1eb7f20 c1eb7e90
7dc0: c1eb7dfc c036b860 c1cdece0 c1854180 00000000 00000001 c1eb6000 fffffdee
7de0: c1eb7e1c c1eb7df0 c020c2c4 000005a0 00000000 c1854154 c18540e8 c1eb7e90
7e00: c1eb7f20 01fa1d09 00000000 00000001 c1eb7e5c c1eb7e20 c00663e0 c0065f10
7e20: 00000000 6221bca6 c1cdece0 c1854180 ee6b2800 01fa1d09 00000000 c18540e8
7e40: c1cdece0 c1eb7f78 c1eb6000 fffffdee c1eb7e84 c1eb7e60 c00c6390 c0066378
7e60: 01fa1d09 00000000 c1eb7e90 c1cdece0 c1eb7e90 c1eb7f20 c1eb7f4c c1eb7e88
7e80: c0083d8c c00c6378 01fa1d09 00000000 47cb50de 00000406 00000000 00000001
7ea0: ffffffff c1cdece0 00000000 00000000 00000000 00000000 c1de3060 c1eb7f75
7ec0: 00000000 00000000 79999999 c1de3060 c00529ac c1eb7ed4 c1eb7ed4 00000000
7ee0: 01fa1d09 00000000 c1eb7f2c c1eb7ef8 c003670c c0035c10 000005a0 00000000
7f00: 00000000 29800000 37b14735 4071f2d4 00000000 00000000 c1eb6120 00000000
7f20: 4001e000 000005a0 c1cdece0 4001e000 c1eb7f78 000005a0 c002a40c 00900004
7f40: c1eb7f74 c1eb7f50 c0084678 c0083ce0 00000007 00000002 01fa1d09 00000000
7f60: c1cdece0 00000004 c1eb7fa4 c1eb7f78 c0084b30 c00845d0 01fa1d09 00000000
7f80: ee00f180 00000000 00000100 000005a0 4001e000 0004de88 00000000 c1eb7fa8
7fa0: c0029be0 c0084afc 000005a0 4001e000 00000004 4001e000 000005a0 00000000
7fc0: 000005a0 4001e000 0004de88 000005a0 000005a0 00000000 0004c720 beec9778
7fe0: 00000000 beec96e8 4021db28 4026d2a4 60000010 00000004 00000000 00000000
Backtrace:
[<c002dc18>] (__bug+0x0/0x2c) from [<c0080be8>]
(cache_alloc_refill+0x130/0x580)
[<c0080ab8>] (cache_alloc_refill+0x0/0x580) from [<c0080a80>]
(kmem_cache_alloc)
[<c0080a30>] (kmem_cache_alloc+0x0/0x88) from [<c00da3cc>]
(journal_add_journal)
 r7:c03573d0 r6:c0377c78 r5:00000000 r4:c1859710
[<c00da390>] (journal_add_journal_head+0x0/0x170) from [<c00d7338>]
(journal_di)
 r8:00000000 r7:c1dd45c0 r6:c18523c8 r5:c1859710 r4:c1859710
[<c00d72f8>] (journal_dirty_data+0x0/0x170) from [<c00c8314>]
(ext3_journal_dir)
 r8:00000000 r7:000002a9 r6:c18523c8 r5:c1859710 r4:c1859710
[<c00c82f8>] (ext3_journal_dirty_data+0x0/0x4c) from [<c00c7498>]
(walk_page_bu)
 r6:c1859710 r5:00001000 r4:c1859710
[<c00c7420>] (walk_page_buffers+0x0/0xac) from [<c00ca078>]
(ext3_ordered_write)
[<c00c9ff0>] (ext3_ordered_write_end+0x0/0x12c) from [<c0065818>]
(generic_file)
[<c0065688>] (generic_file_buffered_write+0x0/0x634) from [<c0066318>]
(__gener)
[<c0065f00>] (__generic_file_aio_write_nolock+0x0/0x468) from [<c00663e0>]
(gen)
[<c0066368>] (generic_file_aio_write+0x0/0xf4) from [<c00c6390>]
(ext3_file_wri)
[<c00c6368>] (ext3_file_write+0x0/0xa8) from [<c0083d8c>]
(do_sync_write+0xbc/0)
 r7:c1eb7f20 r6:c1eb7e90 r5:c1cdece0 r4:c1eb7e90
[<c0083cd0>] (do_sync_write+0x0/0x10c) from [<c0084678>]
(vfs_write+0xb8/0x148)
[<c00845c0>] (vfs_write+0x0/0x148) from [<c0084b30>] (sys_write+0x44/0x70)
 r7:00000004 r6:c1cdece0 r5:00000000 r4:01fa1d09
[<c0084aec>] (sys_write+0x0/0x70) from [<c0029be0>]
(ret_fast_syscall+0x0/0x2c)
 r6:0004de88 r5:4001e000 r4:000005a0
Code: e1a01000 e59f000c eb0048bd e3a03000 (e5833000)
---[ end trace 1880fb840361b0a2 ]---
Segmentation fault


Any pointers would be very much appreciated.

ZL