Dmesg not being dumped

Nikolay Borisov kernel at
Wed Aug 19 04:10:21 PDT 2015


On 08/19/2015 12:02 PM, Baoquan He wrote:
> On 08/19/15 at 09:21am, Nikolay Borisov wrote:
>> Hello,
>> I've recently noticed that when creating crashdumps the dmesg is not
>> being saved. The error reported is this: "Missing the struct log size
>> export". I've tested with both kernel 4.1.1 and 3.12.28. My version of
>> kexec tools is : kexec-tools 2.0.9 released 04 June 2015. The kernel has
>> been compiled with debugging info so the respective symbol should be
>> exported but apparently it is not. Any ideas how to debug that?
> That would be more helpful if you can attach the 1st kernel and kdump
> kernel console log.

I just tested with 4.1.6 with the same result. I'm sending you a link to
the bzImage in question ( I assume
you meant the bzImage, if you need I can provide the vmlinux as well).
Unfortunately, I couldn't figure how to obtain the log of kdump in
textual format (and didn't want to send pictures). Here are the 3
relevant lines (from memory):

Saving vmcore-dmesg.txt
Missing the struct log size export
Error saving vmcore-dmesg.txt.

Yet, when I load the crashdump inside the 'crash' utility and invoke the
'log' command the dmesg log is there. Whereas the
vmcore-dmesg-incomplete.txt is empty.

>> [Please CC me as I'm not subscribed to the mailing list.]
>> Regards,
>> Nikolay
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