kdump cp /proc/vmcore exiting with "Invalid Argument" Error

[Sujit V]

Tried readelf on the /proc/vmcore but gave the below error. The
readelf worked correctly on another binary.

kdump shell>/sbin/readelf -l /proc/vmcore
readelf: Error: Cannot stat input file /proc/vmcore.


Anything else I could try.?


On Sat, Feb 6, 2010 at 1:41 AM, Bernhard Walle <bernhard at bwalle.de> wrote:
>
>
>
> Am 06.02.2010 03:45, schrieb Sujit V:
>> I have integrated the kdump in our linux 2.6.23 based kernel. If I do
>> echo c > /proc/sysrq-trigger then it boots the kdump kernel & I use
>> the cp /proc/vmcore /local/crash/vmcore-incomplete
>>
>> On a new x86 based hardware (32 bit PAE kernel)  the "cp /proc/vmcore
>> " command exits prematurely.
>>
>> cp -v /proc/vmcore /local/crash/vmcore-incomplete
>>       cp: reading `/proc/vmcore': Invalid argument  >>> Error >>
>>
>> ls -l /local/crash/
>> total 115588
>> -r--------    1 0        0        2526724096 Feb  5 03:09 vmcore-incomplete
>>
>> ls -l /proc/vmcore
>> -r--------    1 0        0        4153763584 Feb  5 03:16 /proc/vmcore
>>
>>
>> Every time I trigger kdump the cp command exits after copying
>> 2526724096 bytes. So I thought it might be a file size issue.
>> Googling pointed out a patch in include/linux/proc_fs.h
>
> I would compare 'readelf -l /proc/vmcore' (ELF program headers) and map
> the file offset 2526724096 to the physical memory that belongs to that
> file offset. Maybe accessing that physical memory fails for some reason.
>
>> struct vmcore {
>> struct list_head list;
>> unsigned long long paddr;
>> - unsigned long size;
>> + unsigned long long size;
>> loff_t offset;
>>
>> I checked my kernel & it already has this patch.
>
> I don't think that this is the problem because 2526724096 is between 2G
> and 4G, so it doesn't point to some "magic border".
>
>
> Regards,
> Bernhard
>
>
>