[CentOS] Running CentOS 4.6 domUs on CentOS 5.1 dom0 and domUs crash

  I have a CentOS 5.1 dom0 running on a machine with two cores and 4gb 
of memory. It runs three 4.6 domUs and one 5.1 domU. Just out of the 
blue the other night all the 4.6 domUs crashed, but the dom0 stayed up. 
I ran xm console (domU-name) and got the Oops information below. I 
didn't get anything from the 5.1 domU. I think it had been rebooted a 
few days before and hadn't come up because of a initrd issue.

First 4.6 domU:

kernel BUG at arch/i386/mm/pgtable-xen.c:306!
invalid operand: 0000 [#1]
SMP
Modules linked in: md5 ipv6 sunrpc dm_mirror dm_mod xennet ext3 jbd xenblk
CPU:    0
EIP:    0061:[<c011163a>]    Not tainted VLI
EFLAGS: 00010282   (2.6.9-55.0.12.ELxenU)
EIP is at pgd_ctor+0x1d/0x26
eax: fffffff4   ebx: 00000000   ecx: f5392000   edx: 00000000
esi: c19fdd80   edi: e8f6a700   ebp: 00000001   esp: e0e45de4
ds: 007b   es: 007b   ss: 0068
Process crond (pid: 32004, threadinfo=e0e45000 task=eb4443f0)
Stack: c0141bbd cc57b000 c19fdd80 00000001 cc57b000 e8f6a700 c19fdd80 
c19fde40
       c0141d3f c19fdd80 e8f6a700 00000001 c19fdd80 e8f6a700 cc57b000 
00000010
       00000001 000000d0 c1a1b080 0000000c c19fde08 c19fdd80 c0141f2e 
c19fdd80
Call Trace:
 [<c0141bbd>] cache_init_objs+0x35/0x56
 [<c0141d3f>] cache_grow+0xfb/0x187
 [<c0141f2e>] cache_alloc_refill+0x163/0x19c
 [<c0142149>] kmem_cache_alloc+0x67/0x97
 [<c0111671>] pgd_alloc+0x17/0x336
 [<c01199d4>] mm_init+0xd7/0x116
 [<c01199e4>] mm_init+0xe7/0x116
 [<c0119a3d>] mm_alloc+0x2a/0x31
 [<c0163097>] do_execve+0x82/0x210
 [<c0105d79>] sys_execve+0x2c/0x8e
 [<c010737f>] syscall_call+0x7/0xb
Code: 74 02 66 a5 a8 01 74 01 a4 5e 5b 5e 5f c3 80 3d 04 07 2f c0 00 75 
1c 6a 20 6a 00 ff 74 24 0c e8 ce 37 00 00 83 c4 0c 85 c0 74 08 <0f> 0b 
32 01 ed 33 27 c0 c3 80 3d 04 07 2f c0 00 75 0d c7 44 24
 <0>Fatal exception: panic in 5 seconds
Kernel panic - not syncing: Fatal exception



Second 4.6 domU:

kernel BUG at arch/i386/mm/pgtable-xen.c:306!
invalid operand: 0000 [#1]
SMP
Modules linked in: nfsd exportfs lockd nfs_acl md5 ipv6 sunrpc dm_mirror 
dm_mod xennet ext3 jbd xenblk
CPU:    0
EIP:    0061:[<c011163a>]    Not tainted VLI
EFLAGS: 00010282   (2.6.9-55.0.12.ELxenU)
EIP is at pgd_ctor+0x1d/0x26
eax: fffffff4   ebx: 00000000   ecx: f5392000   edx: 00000000
esi: c19fdd80   edi: e69f4c40   ebp: 00000001   esp: e7282d6c
ds: 007b   es: 007b   ss: 0068
Process nrpe (pid: 1936, threadinfo=e7282000 task=e72cf770)
Stack: c0141bbd c7ebb000 c19fdd80 00000001 c7ebb000 e69f4c40 c19fdd80 
c19fde40
       c0141d3f c19fdd80 e69f4c40 00000001 c19fdd80 e69f4c40 c7ebb000 
00000010
       00000001 000000d0 c1a1b080 0000000c c19fde08 c19fdd80 c0141f2e 
c19fdd80
Call Trace:
 [<c0141bbd>] cache_init_objs+0x35/0x56
 [<c0141d3f>] cache_grow+0xfb/0x187
 [<c0141f2e>] cache_alloc_refill+0x163/0x19c
 [<c0142149>] kmem_cache_alloc+0x67/0x97
 [<c0111671>] pgd_alloc+0x17/0x336
 [<c01199d4>] mm_init+0xd7/0x116
 [<c01199e4>] mm_init+0xe7/0x116
 [<c0119c8a>] copy_mm+0xbb/0x396
 [<c0141f1f>] cache_alloc_refill+0x154/0x19c
 [<c011aa5a>] copy_process+0x6b5/0xb0b
 [<c011af9d>] do_fork+0x8a/0x16b
 [<c020f4c4>] sys_socketcall+0x113/0x202
 [<c0105d2c>] sys_clone+0x24/0x28
 [<c010737f>] syscall_call+0x7/0xb
Code: 74 02 66 a5 a8 01 74 01 a4 5e 5b 5e 5f c3 80 3d 04 07 2f c0 00 75 
1c 6a 20 6a 00 ff 74 24 0c e8 ce 37 00 00 83 c4 0c 85 c0 74 08 <0f> 0b 
32 01 ed 33 27 c0 c3 80 3d 04 07 2f c0 00 75 0d c7 44 24
 <0>Fatal exception: panic in 5 seconds
Kernel panic - not syncing: Fatal exception


Third 4.6 domU:
kernel BUG at arch/i386/mm/pgtable-xen.c:306!
invalid operand: 0000 [#1]
SMP
Modules linked in: md5 ipv6 sunrpc dm_mirror dm_mod xennet ext3 jbd xenblk
CPU:    0
EIP:    0061:[<c011163a>]    Not tainted VLI
EFLAGS: 00010282   (2.6.9-55.0.12.ELxenU)
EIP is at pgd_ctor+0x1d/0x26
eax: fffffff4   ebx: 00000000   ecx: f5392000   edx: 00000000
esi: c15fdd80   edi: d3f312e0   ebp: 00000001   esp: ca9c4de4
ds: 007b   es: 007b   ss: 0068
Process qmail-rspawn (pid: 23442, threadinfo=ca9c4000 task=da68c2b0)
Stack: c0141bbd ced8c000 c15fdd80 00000001 ced8c000 d3f312e0 c15fdd80 
c15fde40
       c0141d3f c15fdd80 d3f312e0 00000001 c15fdd80 d3f312e0 ced8c000 
00000010
       00000001 000000d0 c1613080 0000000c c15fde08 c15fdd80 c0141f2e 
c15fdd80
Call Trace:
 [<c0141bbd>] cache_init_objs+0x35/0x56
 [<c0141d3f>] cache_grow+0xfb/0x187
 [<c0141f2e>] cache_alloc_refill+0x163/0x19c
 [<c0142149>] kmem_cache_alloc+0x67/0x97
 [<c0111671>] pgd_alloc+0x17/0x336
 [<c01199d4>] mm_init+0xd7/0x116
 [<c01199e4>] mm_init+0xe7/0x116
 [<c0119a3d>] mm_alloc+0x2a/0x31
 [<c0163097>] do_execve+0x82/0x210
 [<c0105d79>] sys_execve+0x2c/0x8e
 [<c010737f>] syscall_call+0x7/0xb
Code: 74 02 66 a5 a8 01 74 01 a4 5e 5b 5e 5f c3 80 3d 04 07 2f c0 00 75 
1c 6a 20 6a 00 ff 74 24 0c e8 ce 37 00 00 83 c4 0c 85 c0 74 08 <0f> 0b 
32 01 ed 33 27 c0 c3 80 3d 04 07 2f c0 00 75 0d c7 44 24
 <0>Fatal exception: panic in 5 seconds
Kernel panic - not syncing: Fatal exception