/sbin/kexec became zero size... Anyone else?

/sbin/kexec became zero size... Anyone else?

[Jay Lan]

Hi,

My root disk was populated with sles10sp2, but the kernel was
2.6.27-rc5 and /sbin/kexec was built from 2.0.0 version.

Many times when kdump kernel failed early i found  after reboot that
/sbin/kexec became zero size. There was no warning on executing
'/etc/init.d/kdump start' when /sbin/kexec is zero size. I have
no idea when and how that happened.

Has anyone else seen this problem?

Thanks,
jay


a4700rac:/sbin # ll kexec*
-rwxr-xr-x 1 root root      0 2008-09-17 12:41 kexec
-rwxr-xr-x 1 root root 387635 2008-07-23 07:25 kexec-2.0.0
-r-xr-xr-x 1 root root 320632 2008-04-21 17:31 kexec-sles10sp2
a4700rac:/sbin # /etc/init.d/kdump start
Loading kdump Loading kdump kernel: /sbin/kexec -p
/boot/vmlinuz-2.6.27-rc5-default --append="CRASH=1  root=/dev/sda8
shub2 console=ttySG0,115200  thash_entries=2097152  ro elevator=deadline
sysrq=1 reset_devices irqpoll maxcpus=1  3"
--initrd=/boot/initrd-2.6.27-rc5-default --noio
                                                                     done
a4700rac:/sbin #


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: /sbin/kexec became zero size... Anyone else?

[Simon Horman]

On Wed, Sep 17, 2008 at 02:07:15PM -0700, Jay Lan wrote:
> Hi,
> 
> My root disk was populated with sles10sp2, but the kernel was
> 2.6.27-rc5 and /sbin/kexec was built from 2.0.0 version.
> 
> Many times when kdump kernel failed early i found  after reboot that
> /sbin/kexec became zero size. There was no warning on executing
> '/etc/init.d/kdump start' when /sbin/kexec is zero size. I have
> no idea when and how that happened.
> 
> Has anyone else seen this problem?

Is it possible that this is caused by filesystem corruption?

-- 
Simon Horman
  VA Linux Systems Japan K.K., Sydney, Australia Satellite Office
  H: www.vergenet.net/~horms/             W: www.valinux.co.jp/en


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: /sbin/kexec became zero size... Anyone else?

[Jay Lan]

Simon Horman wrote:
> On Wed, Sep 17, 2008 at 02:07:15PM -0700, Jay Lan wrote:
>> Hi,
>>
>> My root disk was populated with sles10sp2, but the kernel was
>> 2.6.27-rc5 and /sbin/kexec was built from 2.0.0 version.
>>
>> Many times when kdump kernel failed early i found  after reboot that
>> /sbin/kexec became zero size. There was no warning on executing
>> '/etc/init.d/kdump start' when /sbin/kexec is zero size. I have
>> no idea when and how that happened.
>>
>> Has anyone else seen this problem?
> 
> Is it possible that this is caused by filesystem corruption?

I found the problems, which i can not reliably reproduce, happened
when i ran into kdump kernel boot failure (yet not every time.)
What puzzled me was why only /sbin/kexec was affected.

I can not explain what caused it (otherwise i would be able to
reproduce it) and do not know where my finger should point to. ;)
The good news is since i fixed the kernel boot problem it has not
happened any more.

The distros probably can add a check against zero-sized kexec
in /etc/init.d/kdump script though.

Thanks,
 - jay


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: /sbin/kexec became zero size... Anyone else?

[Neil Horman]

On Tue, Sep 23, 2008 at 09:41:50AM -0700, Jay Lan wrote:
> Simon Horman wrote:
> > On Wed, Sep 17, 2008 at 02:07:15PM -0700, Jay Lan wrote:
> >> Hi,
> >>
> >> My root disk was populated with sles10sp2, but the kernel was
> >> 2.6.27-rc5 and /sbin/kexec was built from 2.0.0 version.
> >>
> >> Many times when kdump kernel failed early i found  after reboot that
> >> /sbin/kexec became zero size. There was no warning on executing
> >> '/etc/init.d/kdump start' when /sbin/kexec is zero size. I have
> >> no idea when and how that happened.
> >>
> >> Has anyone else seen this problem?
> > 
> > Is it possible that this is caused by filesystem corruption?
> 
> I found the problems, which i can not reliably reproduce, happened
> when i ran into kdump kernel boot failure (yet not every time.)
> What puzzled me was why only /sbin/kexec was affected.
> 
This is why most kdump implementations capture vmcore from an initramfs, since
a crash means that you may not be able to trust the integrity of the filesystems
that were mounted before the panic.


> I can not explain what caused it (otherwise i would be able to
> reproduce it) and do not know where my finger should point to. ;)
> The good news is since i fixed the kernel boot problem it has not
> happened any more.
> 
> The distros probably can add a check against zero-sized kexec
> in /etc/init.d/kdump script though.
> 
Theres really not a need to.  Filesystems can be corrupted by crashes, thats why
we capture cores from the initrd.  We need to be able to trust the rest of the
system to scan filesystems and do their best to recover when filsystems loose
data.

Regards
Neil
 
> Thanks,
>  - jay
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

-- 
/***************************************************
 *Neil Horman
 *Senior Software Engineer
 *Red Hat, Inc.
 *nhorman@redhat.com
 *gpg keyid: 1024D / 0x92A74FA1
 *http://pgp.mit.edu
 ***************************************************/

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: /sbin/kexec became zero size... Anyone else?

[Jay Lan]

Neil Horman wrote:
> On Tue, Sep 23, 2008 at 09:41:50AM -0700, Jay Lan wrote:
>> Simon Horman wrote:
>>> On Wed, Sep 17, 2008 at 02:07:15PM -0700, Jay Lan wrote:
>>>> Hi,
>>>>
>>>> My root disk was populated with sles10sp2, but the kernel was
>>>> 2.6.27-rc5 and /sbin/kexec was built from 2.0.0 version.
>>>>
>>>> Many times when kdump kernel failed early i found  after reboot that
>>>> /sbin/kexec became zero size. There was no warning on executing
>>>> '/etc/init.d/kdump start' when /sbin/kexec is zero size. I have
>>>> no idea when and how that happened.
>>>>
>>>> Has anyone else seen this problem?
>>> Is it possible that this is caused by filesystem corruption?
>> I found the problems, which i can not reliably reproduce, happened
>> when i ran into kdump kernel boot failure (yet not every time.)
>> What puzzled me was why only /sbin/kexec was affected.
>>
> This is why most kdump implementations capture vmcore from an initramfs, since
> a crash means that you may not be able to trust the integrity of the filesystems
> that were mounted before the panic.
> 
> 
>> I can not explain what caused it (otherwise i would be able to
>> reproduce it) and do not know where my finger should point to. ;)
>> The good news is since i fixed the kernel boot problem it has not
>> happened any more.
>>
>> The distros probably can add a check against zero-sized kexec
>> in /etc/init.d/kdump script though.
>>
> Theres really not a need to.  Filesystems can be corrupted by crashes, thats why
> we capture cores from the initrd.  We need to be able to trust the rest of the
> system to scan filesystems and do their best to recover when filsystems loose
> data.

Hi Neil,

Which rhel release starts doing this?

Thanks,
 - jay


> 
> Regards
> Neil
>  
>> Thanks,
>>  - jay
>>
>>
>> _______________________________________________
>> kexec mailing list
>> kexec@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec
> 


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: /sbin/kexec became zero size... Anyone else?

[Neil Horman]

On Tue, Sep 23, 2008 at 01:32:19PM -0700, Jay Lan wrote:
> Neil Horman wrote:
> > On Tue, Sep 23, 2008 at 09:41:50AM -0700, Jay Lan wrote:
> >> Simon Horman wrote:
> >>> On Wed, Sep 17, 2008 at 02:07:15PM -0700, Jay Lan wrote:
> >>>> Hi,
> >>>>
> >>>> My root disk was populated with sles10sp2, but the kernel was
> >>>> 2.6.27-rc5 and /sbin/kexec was built from 2.0.0 version.
> >>>>
> >>>> Many times when kdump kernel failed early i found  after reboot that
> >>>> /sbin/kexec became zero size. There was no warning on executing
> >>>> '/etc/init.d/kdump start' when /sbin/kexec is zero size. I have
> >>>> no idea when and how that happened.
> >>>>
> >>>> Has anyone else seen this problem?
> >>> Is it possible that this is caused by filesystem corruption?
> >> I found the problems, which i can not reliably reproduce, happened
> >> when i ran into kdump kernel boot failure (yet not every time.)
> >> What puzzled me was why only /sbin/kexec was affected.
> >>
> > This is why most kdump implementations capture vmcore from an initramfs, since
> > a crash means that you may not be able to trust the integrity of the filesystems
> > that were mounted before the panic.
> > 
> > 
> >> I can not explain what caused it (otherwise i would be able to
> >> reproduce it) and do not know where my finger should point to. ;)
> >> The good news is since i fixed the kernel boot problem it has not
> >> happened any more.
> >>
> >> The distros probably can add a check against zero-sized kexec
> >> in /etc/init.d/kdump script though.
> >>
> > Theres really not a need to.  Filesystems can be corrupted by crashes, thats why
> > we capture cores from the initrd.  We need to be able to trust the rest of the
> > system to scan filesystems and do their best to recover when filsystems loose
> > data.
> 
> Hi Neil,
> 
> Which rhel release starts doing this?
> 
Not sure what you mean.  Which rhel releases attempt to recover filesystems on
boot?  Linux has done that with fsck for years.  Which RHEL releases have
allowed vmcore capture from an initrd with kdump?  Read the man page, its been
available since GA.

Neil

> Thanks,
>  - jay
> 
> 
> > 
> > Regards
> > Neil
> >  
> >> Thanks,
> >>  - jay
> >>
> >>
> >> _______________________________________________
> >> kexec mailing list
> >> kexec@lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/kexec
> > 
> 

-- 
/***************************************************
 *Neil Horman
 *Senior Software Engineer
 *Red Hat, Inc.
 *nhorman@redhat.com
 *gpg keyid: 1024D / 0x92A74FA1
 *http://pgp.mit.edu
 ***************************************************/

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

Re: /sbin/kexec became zero size... Anyone else?

[Neil Horman]

On Tue, Sep 23, 2008 at 01:32:19PM -0700, Jay Lan wrote:
> Neil Horman wrote:
> > On Tue, Sep 23, 2008 at 09:41:50AM -0700, Jay Lan wrote:
> >> Simon Horman wrote:
> >>> On Wed, Sep 17, 2008 at 02:07:15PM -0700, Jay Lan wrote:
> >>>> Hi,
> >>>>
> >>>> My root disk was populated with sles10sp2, but the kernel was
> >>>> 2.6.27-rc5 and /sbin/kexec was built from 2.0.0 version.
> >>>>
> >>>> Many times when kdump kernel failed early i found  after reboot that
> >>>> /sbin/kexec became zero size. There was no warning on executing
> >>>> '/etc/init.d/kdump start' when /sbin/kexec is zero size. I have
> >>>> no idea when and how that happened.
> >>>>
> >>>> Has anyone else seen this problem?
> >>> Is it possible that this is caused by filesystem corruption?
> >> I found the problems, which i can not reliably reproduce, happened
> >> when i ran into kdump kernel boot failure (yet not every time.)
> >> What puzzled me was why only /sbin/kexec was affected.
> >>
> > This is why most kdump implementations capture vmcore from an initramfs, since
> > a crash means that you may not be able to trust the integrity of the filesystems
> > that were mounted before the panic.
> > 
> > 
> >> I can not explain what caused it (otherwise i would be able to
> >> reproduce it) and do not know where my finger should point to. ;)
> >> The good news is since i fixed the kernel boot problem it has not
> >> happened any more.
> >>
> >> The distros probably can add a check against zero-sized kexec
> >> in /etc/init.d/kdump script though.
> >>
> > Theres really not a need to.  Filesystems can be corrupted by crashes, thats why
> > we capture cores from the initrd.  We need to be able to trust the rest of the
> > system to scan filesystems and do their best to recover when filsystems loose
> > data.
> 
> Hi Neil,
> 
> Which rhel release starts doing this?
> 
> Thanks,
>  - jay
> 
Its always been that way.
Neil

> 
> > 
> > Regards
> > Neil
> >  
> >> Thanks,
> >>  - jay
> >>
> >>
> >> _______________________________________________
> >> kexec mailing list
> >> kexec@lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/kexec
> > 
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
> 

_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec