linux-kernel - Re: /proc/kcore has a unreasonable size(281474974617600) in x86

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Message-ID: <4A28E5C9.6010408@oracle.com>
Date:	Fri, 05 Jun 2009 17:30:49 +0800
From:	Tao Ma <tao.ma@...cle.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	Américo Wang <xiyou.wangcong@...il.com>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>,
	Yinghai Lu <yinghai@...nel.org>,
	Andi Kleen <ak@...ux.intel.com>
Subject: Re: /proc/kcore has a unreasonable size(281474974617600) in x86_64
  2.6.30-rc8.



Andrew Morton wrote:
> On Fri, 5 Jun 2009 17:09:54 +0800 Am__rico Wang <xiyou.wangcong@...il.com> wrote:
> 
>> On Fri, Jun 5, 2009 at 4:57 PM, Tao Ma<tao.ma@...cle.com> wrote:
>>>
>>> Amerigo Wang wrote:
>>>> On Fri, Jun 05, 2009 at 02:59:46PM +0800, Tao Ma wrote:
>>>>> Andrew Morton wrote:
>>>>>> On Fri, 05 Jun 2009 12:03:52 +0800 Tao Ma <tao.ma@...cle.com> wrote:
>>>>>>
>>>>>>> Hi list,
>>>>>>> __ __ __ In 2.6.30-rc8, /proc/kcore in x86_64's size is unreasonable large
>>>>>>> to be 281474974617600.
>>>>>>> While in a x86 box, it is 931131392 which looks sane.
>>>>>>>
>>>>>>> [root@...t8 ~]# ll /proc/kcore
>>>>>>> -r-------- 1 root root 281474974617600 Jun __5 11:15 /proc/kcore
>>>>>>>
>>>>>>> [root@...s2-test9 ~]$ ll /proc/kcore
>>>>>>> -r-------- 1 root root 931131392 Jun __5 11:58 /proc/kcore
>>>>>>>
>>>>>>> I just noticed this when kexec fails in "Can't find kernel text map
>>>>>>> area from kcore".
>>>>>>>
>>>>>>> Is there something wrong?
>>>>>>>
>>>>>> fs/proc/kcore.c hasn't changed since October last year. __Was 2.6.29 OK?
>>>>>> Earlier kernels?
>>>>> with 2.6.29, ls shows the same output.
>>>>> [root@...t8 ~]# ll /proc/kcore
>>>>> -r-------- 1 root root 281474974617600 Jun __5 14:35 /proc/kcore
>>>>
>>>> Thanks.
>>>>
>>>> It looks like the value of 'high_memory' is insane..
>>>> Can you get its value on your machine? You can add a printk() or use
>>>> systemtap etc..
>>> Just did that.
>>> Also a strange number.
>>> high memory 18446612137615818752.
>>>
> 
> (top-posting repaired)
> 
>> Add some Cc: to x86 people. :)
>>
>> Yinghai?
>>
> 
> Please send the boot logs: dmesg -s 1000000 > foo
attached.

Thanks.
Tao

View attachment "foo" of type "text/plain" (35344 bytes)