makedumpfile: support for newer kernels [v4.9 onwards]

[Abhishek Shah]

Hi Pratyush/Dave,

On Tue, Jun 13, 2017 at 1:36 PM, Pratyush Anand <panand at redhat.com> wrote:
> Hi Abhishek,
>
> On Thursday 08 June 2017 11:30 AM, Abhishek Shah wrote:
>>
>> Hi Pratyush,
>>
>> Kernel config:
>> ARM64_VA_BITS_48 [=y]
>> ARM64_PAGE_SHIFT [=12]
>> RANDOMIZE_BASE [=n]
>> ARM64_4K_PAGES [=y]
>
> These are the only variable configs on which arm64 makedumpfile depends. I
> tested with above configuration and things were working fine.
>
> I used 4.11 based kernel and  crash-7.1.9.
>
> BTW, which version of crash utility do you use. If you are not at latest can
> you please try with latest.
>
I was using crash 7.1.9++ with head commit
5c52842a58a2602dba81de71831af98b2b53c6e0;
I have upgraded my kernel and built the crash utility again; and
following is my setup details now:

kernel: 4.12- rc5
yocto based rootfs: Pyro[2.3] which has kexec 2.0.14 and makedumpfile 1.6.1.
crash: 7.1.9++ [Head: 4d517ad28acd845fe6e91360e645cf0446a4757b]

The output generated by makedumpfile gets processed by crash utility
if I use following command:
makedumpfile -E /proc/vmcore vmcore

But, the output generated by following command (which I used while
reporting the issue) gives the "seek error" while being processed by
crash.
makedumpfile /proc/vmcore vmcore

(As a result?), output from following command gives "seek error" as
well while being processed by crash:
makedumpfile -c /proc/vmcore vmcore

makedumpfile Manual suggests:
"-E
Create DUMPFILE in the ELF format.
This option cannot be specified with -c option, because the ELF format
does not support compressed data."
So only elf formatted output from makedumpfile gets processed by crash.

@Pratyush, Thanks for testing and verifying the kernel configuration
for arm64 makedumpfile.
When you say things were working fine for you,  what exact
makedumpfile command did you use??

Regards,
Abhishek