From owner-freebsd-current Sun Nov 17 22: 2:35 2002 Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 35A1E37B401; Sun, 17 Nov 2002 22:02:34 -0800 (PST) Received: from mailman.zeta.org.au (mailman.zeta.org.au [203.26.10.16]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0423F43E3B; Sun, 17 Nov 2002 22:02:33 -0800 (PST) (envelope-from bde@zeta.org.au) Received: from bde.zeta.org.au (bde.zeta.org.au [203.2.228.102]) by mailman.zeta.org.au (8.9.3/8.8.7) with ESMTP id RAA25116; Mon, 18 Nov 2002 17:02:30 +1100 Date: Mon, 18 Nov 2002 17:15:18 +1100 (EST) From: Bruce Evans X-X-Sender: bde@gamplex.bde.org To: Robert Watson Cc: Thierry Herbelot , Subject: Re: SMP stability ? [was Re: more info from panic from running dnet on SMP kernel] In-Reply-To: Message-ID: <20021118170528.V25596-100000@gamplex.bde.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sun, 17 Nov 2002, Robert Watson wrote: > I've seen several reports that using a serial break to get into ddb is now > quite a bit more reliable than a keyboard break. If you're not already This is a fact. In RELENG_4, the keyboard interrupt handler is a normal tty interrupt handler so it can't interrupt things blocked by spltty(), while the sio interrupt handler is a fast interrupt handler so it can interrupt almost anything (anything not blocked by disable_intr(), which should be everything except fast interrupt handlers and the entry code for normal interrupt handlers). Things are much more broken in -current: the keyboard interrupt handler is non-MPSAFE so it can't interrupt things blocked by Giant (which is most syscalls), and the sio interrupt handler is a "fast" interrupt handler so it can't interrupt things blocked by critical_enter() (which is too many things for too long, so fast interrupt handlers aren't actually fast). Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message