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Date: Mon, 15 Oct 2001 15:21:47 -0700 (PDT)
From: John Baldwin <jhb@FreeBSD.org>
To: Dag-Erling Smorgrav <des@ofug.org>
Subject: Re: Strike three, you're out
Cc: freebsd-current@FreeBSD.ORG, Doug Barton <DougB@DougBarton.net>,
	Sheldon Hearn <sheldonh@starjuice.net>
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On 13-Oct-01 Dag-Erling Smorgrav wrote:
> Sheldon Hearn <sheldonh@starjuice.net> writes:
>> Perhaps the analogous solution is to be more careful about the use of
>> printf() in the kernel?  Perhaps a similar approach as is used in
>> userland signal handlers should be taken, where a flag is set and later
>> the printf() is performed conditional on the state of the flag?
> 
> I think the correct approach would be for printf() to store the
> printed text in a circular buffer if it detected that printing it
> would cause a locking violation, and for some other part of the kernel
> to check and empty the circular buffer regularly, in a safe context.

Something like that, yes.  Chuck Paterson has patches to do all this for our
printf() if I can extract them.  It basically ends up with 3 different versions
of printf in the kernel.  I'll see if I can't get ahold of them.

-- 

John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/
PGP Key: http://www.baldwin.cx/~john/pgpkey.asc
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/

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