Date: Wed, 21 Jun 2000 08:28:49 -0700 (PDT) From: Matthew Dillon <dillon@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 Message-ID: <200006211528.IAA94804@apollo.backplane.com> References: <Pine.BSF.4.21.0006212159260.4214-100000@besplex.bde.org>
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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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