From owner-freebsd-hackers Tue Oct 20 02:02:43 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id CAA24393 for freebsd-hackers-outgoing; Tue, 20 Oct 1998 02:02:43 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id CAA24373 for ; Tue, 20 Oct 1998 02:02:30 -0700 (PDT) (envelope-from grog@freebie.lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.9.1/8.9.0) with ESMTP id SAA12076; Tue, 20 Oct 1998 18:31:56 +0930 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.1/8.9.0) id SAA21207; Tue, 20 Oct 1998 18:31:48 +0930 (CST) Message-ID: <19981020183148.G21008@freebie.lemis.com> Date: Tue, 20 Oct 1998 18:31:48 +0930 From: Greg Lehey To: Stephen Suryaputra , freebsd-hackers@FreeBSD.ORG Subject: Re: Page fault while in kernel mode, bug? References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.91.1i In-Reply-To: ; from Stephen Suryaputra on Tue, Oct 20, 1998 at 01:38:21AM -0700 WWW-Home-Page: http://www.lemis.com/~grog Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Tuesday, 20 October 1998 at 1:38:21 -0700, Stephen Suryaputra wrote: > Hi, > > I was running a big simulation as root. I know it is wrong but I want to > gain full access to the resources (I tried to setup the limits in > /etc/login.conf with no success... however, this part is mine to figure > out). When I ran the simulation, I found a seems like interesting bug that > you might probably interested in taking a look. Here is a snapshot of the > kernel debugger screen: > >> --- >> Fatal trap 12: page fault while in kernel mode >> fault virtual address = 0x2b2 >> fault code = supervisor read, page not present >> instruction pointer = 0x8:0xf01434ba >> stack pointer = 0x10:0xefbfff2c >> frame pointer = 0x10:0xf2830400 >> code segment = base 0x0, limit 0xfffff, type 0x1b >> = DPL 0, pres 1, def32 1, gran 1 >> processor eflags = interrupt enabled, resume, IOPL = 0 >> current process = 2 (page daemon) >> interrupt mask = >> kernel: type 12 trap, code=0 >> Stopped at _vput+0x1a: movl 0x1c(%ebx),%edx > > This error hit me several times, and for curiosity, I ran exactly the same > simulation on two machines and both get the same error, at the same > instruction pointer. The interesting part, is that the error shows that > there is a page fault in kernel mode. > > I ran it on FreeBSD-2.2.6-RELEASE and while I ran it, several messages > showed up saying that there is not enough swap space. Try adding swap and see if you can still reproduce the bug. > I will be very happy to reproduce the error, and work together with you to > find out what's wrong. Look at the section on kernel debugging in the online handbook (in case of doubt, http://www.freebsd.org/handbook/handbook293.html#634). The most important thing to get is a stack backtrace. That might even be enough to say what is causing the problem. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message