Re: [Xen-devel] Domain0 crash on Bad L1 flags 800000

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

On 12/14/2010 02:03 PM, Kaushik Barde wrote:
> True, I was referring to NX bit disablement causing boot issues 32-bit
> kernel without PAE support. Has anyone tested 64 bit kernels without NX bit?

It does get tested occasionally, and there are some old Intel 64-bit
CPUs which don't support NX.  But running without NX is pretty uncommon
these days, so I'm wondering what the reason for doing so is here.

If there is a genuine NX problem, then it should crash very early.  If
this crash is happening after some amount of uptime, then it suggests
there's some memory corruption setting NX by accident.

    J

> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Jeremy
> Fitzhardinge
> Sent: Tuesday, December 14, 2010 1:57 PM
> To: Kaushik Barde
> Cc: 'Qiangmin Lin'; olaf@xxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx;
> 'fanliang'
> Subject: Re: [Xen-devel] Domain0 crash on Bad L1 flags 800000
>
> On 12/14/2010 01:20 PM, Kaushik Barde wrote:
>> Maybe kernel compiled with PAE (and HIGHMEM64) options, Try recompiling
>> kernel without and see. 
> 32-bit kernels must be compiled with PAE - non-PAE 32-bit PV kernels are
> not supported.
>
> Neither option is relevant on 64-bit.
>
>     J
>
>> -Kaushik
>>
>> -----Original Message-----
>> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Jeremy
>> Fitzhardinge
>> Sent: Tuesday, December 14, 2010 12:37 PM
>> To: Qiangmin Lin
>> Cc: olaf@xxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx; fanliang
>> Subject: Re: [Xen-devel] Domain0 crash on Bad L1 flags 800000
>>
>> On 12/08/2010 06:53 PM, Qiangmin Lin wrote:
>>> Hi all, My dom0 kernel is 2.6.32.12-xen and Xen 3.4.2.
>>> I had closed "No Execute" in BIOS, but I see flags 800000 which mean
>> _PAGE_NX in crash information.
>>
>> This looks like the same bug your colleague fanliang reported to me. Was
>> this after a long period of uptime? What was running at the time?
>>
>> I'm curious why you're using that particular kernel, and why you're
>> running with NX disabled.
>>
>> Thanks,
>> J
>>
>>>  
>>> (XEN) mm.c:720:d0 Bad L1 flags 800000
>>> (XEN) mm.c:4203:d0 ptwr_emulate: could not get_page_from_l1e()
>>> (XEN) domain_crash_sync called from entry.S
>>> (XEN) Domain 0 (vcpu#2) crashed on cpu#2:
>>> (XEN) ----[ Xen-3.4.2  x86_64  debug=n  Not tainted ]----
>>> (XEN) CPU:    2
>>> (XEN) RIP:    e033:[<ffffffffa0375fcc>]
>>> (XEN) RFLAGS: 0000000000010292   EM: 0   CONTEXT: pv guest
>>> (XEN) rax: ffffffffa0376120   rbx: ffff880075222000   rcx:
>> 0000000000000001
>>> (XEN) rdx: ffff88000402b000   rsi: 0000000000000000   rdi:
>> ffff880075222048
>>> (XEN) rbp: ffff880075222000   rsp: ffff8800a5db5ff8   r8:
>> ffffe8ffffeb0588
>>> (XEN) r9:  0000000000000001   r10: 0000000000000000   r11:
>> ffffffffa0376120
>>> (XEN) r12: ffff880075222048   r13: ffff8800c8a69000   r14:
>> ffff880075222058
>>> (XEN) r15: 00007f44fd7802d0   cr0: 0000000080050033   cr4:
>> 00000000000026f0
>>> (XEN) cr3: 00000008dbaf8000   cr2: ffff8800a5db5ff0
>>> (XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: e02b   cs: e033
>>> (XEN) Guest stack trace from rsp=ffff8800a5db5ff8:
>>> (XEN)    ffff8800c8a69000 ffff880075222000 ffff88002bcc6500
>> ffffffffa0376144
>>> (XEN)    ffff8800c8a69000 ffff8800888f7380 ffff8800c8a690f8
>> ffffffffa0377e3c
>>> (XEN)    0000000000000000 0000000000000000 0000000000000000
>> 0000000000000000
>>> (XEN)    ffff8800c8a69000 ffff880075222000 ffff88002bcc6500
>> ffff8800c8a69000
>>> (XEN)    ffff880075222058 ffffffffa0376161 ffff8800c8a69000
>> ffff8800888f7380
>>> (XEN)    ffff8800c8a690f8 ffffffffa0377e3c 0000000000000000
>> 0000000000000000
>>> (XEN)    0000000000000000 0000000000000000 ffff8800c8a69000
>> ffff880075222000
>>> (XEN)    ffff88002bcc6500 ffff8800c8a69000 ffff880075222058
>> ffffffffa0376161
>>> (XEN)    ffff8800c8a69000 ffff8800888f7380 ffff8800c8a690f8
>> ffffffffa0377e3c
>>> (XEN)    0000000000000000 0000000000000000 0000000000000000
>> 0000000000000000
>>> (XEN)    ffff8800c8a69000 ffff880075222000 ffff88002bcc6500
>> ffff8800c8a69000
>>> (XEN)    ffff880075222058 ffffffffa0376161 ffff8800c8a69000
>> ffff8800888f7380
>>> (XEN)    ffff8800c8a690f8 ffffffffa0377e3c 0000000000000000
>> 0000000000000000
>>> (XEN)    0000000000000000 0000000000000000 ffff8800c8a69000
>> ffff880075222000
>>> (XEN)    ffff88002bcc6500 ffff8800c8a69000 ffff880075222058
>> ffffffffa0376161
>>> (XEN)    ffff8800c8a69000 ffff8800888f7380 ffff8800c8a690f8
>> ffffffffa0377e3c
>>> (XEN)    0000000000000000 0000000000000000 0000000000000000
>> 0000000000000000
>>> (XEN)    ffff8800c8a69000 ffff880075222000 ffff88002bcc6500
>> ffff8800c8a69000
>>> (XEN)    ffff880075222058 ffffffffa0376161 ffff8800c8a69000
>> ffff8800888f7380
>>> (XEN)    ffff8800c8a690f8 ffffffffa0377e3c 0000000000000000
>> 0000000000000000
>>> (XEN) Domain 0 crashed: rebooting machine in 5 seconds.
>>> [1182692.327659] BUG: unable to handle kernel
>>> please help me
>>> L
>>>
>>>
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