kdump issues with 4.11 kernel

[Bhupesh Sharma]

On Wed, Nov 29, 2017 at 3:36 PM, Gurumurthy, Anil
<Anil.Gurumurthy at cavium.com> wrote:
>
>
> -----Original Message-----
> From: Bhupesh Sharma [mailto:bhsharma at redhat.com]
> Sent: 29 November 2017 15:16
> To: Gurumurthy, Anil <Anil.Gurumurthy at cavium.com>
> Cc: Dave Young <dyoung at redhat.com>; kexec at lists.infradead.org
> Subject: Re: kdump issues with 4.11 kernel
>
> Hi Anil,
>
> On Wed, Nov 29, 2017 at 2:44 PM, Gurumurthy, Anil <Anil.Gurumurthy at cavium.com> wrote:
>> Thanks. That did help getting kexec to work.
>> However I still do not get a crash dump - echo c  >
>> /proc/sysrq-trigger does not get a crash dump.
>>
>> Any thoughts?
>
> Cam you share the console messages you see when the crash kernel boots? Or do you see nothing after the crash is introduced via echo c
>> /proc/sysrq-trigger
> [Anil]  I do not see any messages after introducing the crash.

There could be several reasons for this:

- crashkernel might be missing some arch/machine specific options.
- It may be that the purgatory sha verification has failed. If your
arch supports a console in purgatory then it is easy to debug this.
- It might be that the crash kernel itself crashed very early. Pass
some earlycon/earlyprintk option for your system to the second kernel
command line.
- Also please share relevant dmesg log of both primary kernel boot and
the commands you use to invoke the crashkernel.

Regards,
Bhupesh


> Generally, depending on your test machine arch, it is useful to use earlycon/earlyprintk to see if the crash kernel produced any useful message until the actual console device became operational.
>
> Can you try setting the earlycon/earlyprintk settings and share the crash kernel logs messages after the same?
>
> Thanks,
> Bhupesh
>
>> -----Original Message-----
>> From: Dave Young [mailto:dyoung at redhat.com]
>> Sent: 29 November 2017 13:09
>> To: Gurumurthy, Anil <Anil.Gurumurthy at cavium.com>
>> Cc: kexec at lists.infradead.org
>> Subject: Re: kdump issues with 4.11 kernel
>>
>> Hi,
>> On 11/29/17 at 05:29am, Gurumurthy, Anil wrote:
>>> Hello,
>>>   I was facing trouble getting a crash dump on 4.11 kernel. Debugging a bit, I see that the kexec run from the cmd line fails. Any ideas on what I could be missing?
>>>
>>> [root at localhost ~]# kexec -p /boot/vmlinuz-`uname -r`
>>> --initrd=/boot/initramfs-`uname -r`kdump.img ELF core (kcore) parse
>>> failed Cannot load /boot/vmlinuz-4.11.12+
>>>
>>
>> Can you try below kexec-tools commit:
>> commit ed15ba1b9977e506637ff1697821d97127b2c919
>> Author: Pratyush Anand <panand at redhat.com>
>> Date:   Wed Mar 1 11:19:42 2017 +0530
>>
>>     build_mem_phdrs(): check if p_paddr is invalid
>>
>> Thanks
>> Dave
>>
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