From: "Randy.Dunlap" <rddunlap@osdl.org>
To: Jim Nelson <james4765@cwazy.co.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
Coywolf Qi Hunt <coywolf@gmail.com>,
Jesper Juhl <juhl-lkml@dif.dk>,
David Howells <dhowells@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: printk loglevel policy?
Date: Sun, 02 Jan 2005 13:41:34 -0800 [thread overview]
Message-ID: <41D86A8E.9090400@osdl.org> (raw)
In-Reply-To: <41D84503.2040808@cwazy.co.uk>
Jim Nelson wrote:
> Alan Cox wrote:
>
>> On Gwe, 2004-12-31 at 02:20, Coywolf Qi Hunt wrote:
>>
>>> Hi all,
>>> Recently, I've seen a lot of add loglevel to printk patches. grep
>>> 'printk("' -r | wc shows me 2433. There are probably 2433 printk
>>> need to patch, is it? What's this printk loglevel policy, all these
>>
>>
>>
>> You would need to work out which were at the start of a newline - most
>> of them are probably just fine and valid
>>
>
> That reminds me of a question I've had inthe back of my head. When you
> have a SMP system wouldn't it be possible to have:
>
> CPU 1 (running func1) CPU 2 (running func2)
> | |
> printk ("foo..."); |
> | printk ("bleh\n");
> printk ("finished\n); |
> printk ("readout from bleh\n";
>
> Is that possible? Especially if the process on CPU 1 slept on a
> semaphore or something similar?
>
> Or does printk() do some tracking that I didn't see as to where in the
> kernel the strings are coming from?
That kind of garbled output has been known to happen, but
the <console_sem> is supposed to prevent that (along with
zap_locks() in kernel/printk.c).
If it still happens, it needs to be fixed.
David Howells (RH) has posted patches that fix it.
--
~Randy
next prev parent reply other threads:[~2005-01-02 21:48 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-31 2:02 [patch] add loglevel to printk in fs/afs/cmservice.c Jesper Juhl
2004-12-31 2:20 ` printk loglevel policy? Coywolf Qi Hunt
2004-12-31 4:07 ` Jim Nelson
2004-12-31 4:34 ` Jesper Juhl
2005-01-02 14:36 ` Alan Cox
2005-01-02 19:01 ` Jim Nelson
2005-01-02 21:41 ` Randy.Dunlap [this message]
2005-01-03 3:17 ` Keith Owens
2005-01-03 3:52 ` Randy.Dunlap
2005-01-03 4:44 ` Jim Nelson
2005-01-04 10:46 ` David Howells
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