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Date: Fri, 28 Dec 2007 21:39:31 +0100
From: Kris Kennaway <kris@FreeBSD.org>
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To: Michael Butler <imb@protected-networks.net>
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Cc: FreeBSD current <freebsd-current@freebsd.org>,
	Jens Schweikhardt <schweikh@schweikhardt.net>
Subject: Re: Garbled shutdown message
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Michael Butler wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Kris Kennaway wrote:
>> Jens Schweikhardt wrote:
>>> If you look at this closely you can find "Syncing (max 60 seconds) for
>>> system process" if you read about every other character. It's always the
>>> third of the three "Waiting" lines. Anyone else seeing this?
>> You have an SMP system and do not have the PRINTF_BUFR option or
>> whatever it is.  Without it multiple CPUs have no synchronization
>> between printfs and will interleave.
> 
> So the recommended value for PRINTF_BUFR_SIZE is ... ?

NOTES has 128 I think.

> In my (very brief) browse through kern/subr_prf.c, I didn't see any
> overflow protection on the stack-allocated buffer ... which makes me
> rather nervous.
 >
> Interleaved text is *way* better than clobbered kernel stack ..

So either fix it if there is a problem or don't use it if you are scared :)

Kris