Re: printk behavioral regression

From: Kay Sievers
Date: Tue Jun 19 2012 - 10:35:10 EST


On Tue, Jun 19, 2012 at 4:04 PM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>> On 19.06.12 at 15:53, Kay Sievers <kay@xxxxxxxx> wrote:
>> On Tue, Jun 19, 2012 at 3:30 PM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>> running 3.5-rc3 on a SLE11 SP1 system, early boot messages (apart
>>> from the very first one) end up in /var/log/messages rather than
>>> /var/log/boot.msg. I didn't dig deep enough yet to figure out what
>>> is causing this, and would hope that you (having contributed most
>>> of the changes between 3.4 and 3.5-rc3) might have an idea.
>>
>> Hmm, no idea really, and why this should change.
>
> Okay, then I'll indeed need to do some debugging.
>
>> /var/log/boot.msg is a SUSE speciality, that, as far as I know, just
>> dumps 'dmesg' after bootup, it has not much to do with the normal
>> syslog/klog logging in /var/log/messages, where all your messages should
>> always end up, and what seems to work for you.

Sure? The /var/log/boot.msg gets overwritten with every reboot, I
don't remember losing all bootup messages in syslog on SUSE; and that
would seriously weird if it behaves like that.

> No, boot messages (at least by default) end up _only_ in
> /var/log/boot.msg, and thus significantly help keeping the size
> of /var/log/messages down. SUSE specialty or not, there
> clearly is some user space visible change here.

Look out for the SUSE tool blogd and how that is involved in getting
these messages from the kernel.

And there is a fix pending in Greg's tree:
http://git.kernel.org/?p=linux/kernel/git/gregkh/driver-core.git;a=commit;h=4a77a5a06ec66ed05199b301e7c25f42f979afdc

which is supposed to fix a different issue, but we can never know ...

Kay
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