initrd and messages in the kernel log

initrd and messages in the kernel log

[Kevin Wilson]

Hello,
Question: in the boot process on my machine (Ubuntu 14), the standard
Ubuntu initrd image is used.
In that process of bootstrapping from initrd, several kernel modules
from the initrd module are used.
I believe that some of these modules are printing module messages
using the standard kernel mechanism.
Question in:  from what I see, these messages do not appear in the
kernel log (/var/log/syslog). Is there a way
to enable getting these messages to the kernel log ?

Kevin

initrd and messages in the kernel log

[Greg KH]

On Fri, Jan 20, 2017 at 10:33:46AM +0200, Kevin Wilson wrote:
> Hello,
> Question: in the boot process on my machine (Ubuntu 14), the standard
> Ubuntu initrd image is used.
> In that process of bootstrapping from initrd, several kernel modules
> from the initrd module are used.
> I believe that some of these modules are printing module messages
> using the standard kernel mechanism.
> Question in:  from what I see, these messages do not appear in the
> kernel log (/var/log/syslog). Is there a way
> to enable getting these messages to the kernel log ?

So some messages are showing up, but not all of them?  How do you know
some are missing?

If you run 'dmesg' do you see all of the messages there?

thanks,

greg k-h

initrd and messages in the kernel log

[Kevin Wilson]

Hello Greg,
Thanks for the quick response.
I investigate more and came to the conclusion that for a specific
network driver, there are messages in kernel log which originate from
initrd and not from the modules under /lib/modules/...
Please let me rephrase the question, I was not clear enough about what
my query is, as the point here is not missing messages:

Is there a way to know which messages in the kernel log are originated
from initrd and which are not ? is there some entry in the log file
that can tell us that all messages before it (till the boot itself)
are originated from initrd and all messages after (till next boot) are
not from initrd but from /lib/modules and/or /boot/vmlinuz?

Thanks,
Kevin







On Fri, Jan 20, 2017 at 10:50 AM, Greg KH <greg@kroah.com> wrote:
> On Fri, Jan 20, 2017 at 10:33:46AM +0200, Kevin Wilson wrote:
>> Hello,
>> Question: in the boot process on my machine (Ubuntu 14), the standard
>> Ubuntu initrd image is used.
>> In that process of bootstrapping from initrd, several kernel modules
>> from the initrd module are used.
>> I believe that some of these modules are printing module messages
>> using the standard kernel mechanism.
>> Question in:  from what I see, these messages do not appear in the
>> kernel log (/var/log/syslog). Is there a way
>> to enable getting these messages to the kernel log ?
>
> So some messages are showing up, but not all of them?  How do you know
> some are missing?
>
> If you run 'dmesg' do you see all of the messages there?
>
> thanks,
>
> greg k-h

initrd and messages in the kernel log

[Greg KH]

On Fri, Jan 20, 2017 at 01:23:41PM +0200, Kevin Wilson wrote:
> Hello Greg,
> Thanks for the quick response.
> I investigate more and came to the conclusion that for a specific
> network driver, there are messages in kernel log which originate from
> initrd and not from the modules under /lib/modules/...
> Please let me rephrase the question, I was not clear enough about what
> my query is, as the point here is not missing messages:
> 
> Is there a way to know which messages in the kernel log are originated
> from initrd and which are not ?

Nope.

> is there some entry in the log file that can tell us that all messages
> before it (till the boot itself) are originated from initrd and all
> messages after (till next boot) are not from initrd but from
> /lib/modules and/or /boot/vmlinuz?

Unless the initrd itself puts a message into the log saying when it
stops and when it transfers control over to your "real" system, no there
is not.

But you should have all of the messages in dmesg, to look at, so there
shouldn't really be a problem here, right?  What exactly is the issue
you are trying to solve?

thanks,

greg k-h