From owner-freebsd-hackers Mon Mar 24 16:00:57 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id QAA21719 for hackers-outgoing; Mon, 24 Mar 1997 16:00:57 -0800 (PST) Received: from who.cdrom.com (who.cdrom.com [204.216.27.3]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id QAA21702 for ; Mon, 24 Mar 1997 16:00:54 -0800 (PST) Received: from root.com (implode.root.com [198.145.90.17]) by who.cdrom.com (8.8.5/8.6.11) with ESMTP id PAA15911 for ; Mon, 24 Mar 1997 15:36:56 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by root.com (8.8.5/8.6.5) with SMTP id PAA11362; Mon, 24 Mar 1997 15:37:47 -0800 (PST) Message-Id: <199703242337.PAA11362@root.com> X-Authentication-Warning: implode.root.com: localhost [127.0.0.1] didn't use HELO protocol To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) cc: hackers@freebsd.org, bmcgover@cisco.com (Brian McGovern) Subject: Re: "double fault" message In-reply-to: Your message of "Mon, 24 Mar 1997 22:00:22 +0100." <19970324220022.VH35420@uriah.heep.sax.de> From: David Greenman Reply-To: dg@root.com Date: Mon, 24 Mar 1997 15:37:47 -0800 Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk >As Brian McGovern wrote: > >> I'm doing some kernel hacking, and my device driver is now getting the >> messge 'panic: double fault', and rebooting. Can anyone let me know >> what a 'double fault' is, so I can go looking for it? Thanks. > >Well, it's two faults in a row. But you already knew this, did you? >:-) > >I think it might happen if you trash the kernel stack. The fault >handler than attempts to run on this stack again, and triggers another >fault. This will finally call the double fault handler, which i >believe runs on its own small stack. Correct. The most likely cause is a recursive function call. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project