From owner-freebsd-smp  Wed Jun 21  8:28:59 2000
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Date: Wed, 21 Jun 2000 08:28:49 -0700 (PDT)
From: Matthew Dillon <dillon@apollo.backplane.com>
Message-Id: <200006211528.IAA94804@apollo.backplane.com>
To: Bruce Evans <bde@zeta.org.au>
Cc: Jason Evans <jasone@canonware.com>, Greg Lehey <grog@lemis.com>,
	Warner Losh <imp@village.org>, The Hermit Hacker <scrappy@hub.org>,
	freebsd-smp@FreeBSD.ORG
Subject: Re: SP Patchset #1 up
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:These were more or less correct, and unrelated to sio.
:
:Note that the low level console drivers must not use any locks or switch
:context, since they need to work in debugger traps which may occur with
:locks in any state.  Old reentrancy bugs in syscons will probably be
:more obvious now.  
:
:Bruce

    Yah.   That's why I replaced them all with mtx_enter_sched_quick(),
    which is the closest equivalent to those requirements.  The spl*()
    calls only work if you are holding GiantMutex, and that obviously
    is not necessarily the case for the kernel printf().

    Believe me, I hit those problems early--- when I could ctl-alt-esc
    into DDB or when a panic would occur and not even print the panic
    message.  I think I have those cases fixed in patch set #1.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>


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