vmcore-dmesg ends with "No program header covering vaddr"

[Baoquan He]

On 04/04/14 at 11:40am, Prasad Koya wrote:
> Thanks for replying Baoquan.
> 
> Our production kernel is 3.4 and it has legacy dmesg buffer. I was
> able to dump it from oldmem. If this change is of any use for
> community I could try submit the patch.

I think your change makes sense. Since if you have this requirement,
other people could have too. You can post your patch and let people
review your patch and discuss.

Thanks
Baoquan

> 
> On Fri, Apr 4, 2014 at 4:14 AM, Baoquan He <bhe at redhat.com> wrote:
> > On 03/14/14 at 10:39pm, Prasad Koya wrote:
> >> Hi
> >>
> >> I'm increasing dmesg buffer size at runtime by passing log_buf_len=1M
> >> (or 512K) at command line. At compile time, I have LOG_BUF_LEN as
> >> 256K. However, when this kernel crashes (crashkernel set at 64M),
> >> vmcore-dmesg fails with below error.
> >>
> >> No program header covering vaddr 0xffff88013ff00000found kexec bug?
> >>
> >> Am I missing something here?
> >>
> >> Thank you.
> >>
> >> Here are some debugs I added to kernel. This is with 3.4 kernel and
> >> I've tried with kexec-tools-2.0.4.
> >>
> >> [    0.000000] log_buf_len_setup: log_buf_len 262144 new 1048576
> >> ffffffff8170b140
> >> [    0.000000] setup_log_buf: early 1 262144 new_log_buf_len 1048576
> >> [    0.000000] log_buf_len: 1048576 ffff880037d58000
> >> [    0.000000] early log buf free: 258671(98%)
> >> [    0.000000] setup_log_buf: early 0 1048576 new_log_buf_len 0
> >> [    0.503752] log_buf_kexec_setup: lbl 1048576 new 0 ffffffff816198c4
> >> logbuf ffff880037d58000
> >> In kdump, running vmcore_dmesg /proc/vmcore
> >> No program header covering vaddr 0xffff88013ff00000found kexec bug?
> >
> > Hi Prasad,
> >
> > Did you try the latest kernel and vmcore-dmesg? Mine is OK. Surely you
> > need apply below patch since it's not merged yet.
> >
> > Author: Lubomir Rintel <lkundrak at v3.sk>
> > Date:   Wed Sep 18 14:21:43 2013 +0200
> >
> >     vmcore-dmesg: Understand >= v3.11-rc4 dmesg
> >
> >     Symbol name changed with the following commit:
> >     62e32ac printk: rename struct log to struct printk_log
> >
> > Thanks
> > Baoquan
> >
> >>
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