Re: /proc/kcore has a unreasonable size(281474974617600) in x86_64 2.6.30-rc8.

Tao Ma
2009-06-05T06:56:52Z

Amerigo Wang wrote:
> On Fri, Jun 05, 2009 at 02:07:58PM +0800, Tao Ma wrote:
>>
>> Amerigo Wang wrote:
>>> On Fri, Jun 05, 2009 at 12:03:52PM +0800, Tao Ma 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@test8 ~]# ll /proc/kcore
>>>> -r-------- 1 root root 281474974617600 Jun 5 11:15 /proc/kcore
>>>>
>>>> [root@ocfs2-test9 ~]$ ll /proc/kcore
>>>> -r-------- 1 root root 931131392 Jun 5 11:58 /proc/kcore
>>> Hmm, what is your physical RAM size on test8?
>>> /proc/kcore looks fine on my x86_64 box.
>> Only 4G.
>
> Hmm, my x86_box has 8G mem, the size of kcore looks much
> saner than the above huge number, but it is still wrong
> according to what the man page describes...
>
> Please do what Andrew said, it will be helpful.
>
>>>> I just noticed this when kexec fails in "Can't find kernel text map
>>>> area from kcore".
>>>>
>>>> Is there something wrong?
>>> It looks like that error message is from userspace?
>> I just started kdump and get the error message.
>
> IIRC, kdump should use /proc/vmcore, instead of /proc/kcore...
> nothing related.
in el5, when start kdump service it will do something like
/sbin/kexec --args-linux -p '--command-line=ro root=LABEL=/ rhgb quiet
irqpoll maxcpus=1' --initrd=/boot/initrd-2.6.18-53.el5kdump.img
/boot/vmlinuz-2.6.18-53.el5

And the error message is from there.

Regards,
Tao