From owner-freebsd-hackers@FreeBSD.ORG Thu Aug 19 19:06:10 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 16FDD16A4CE for ; Thu, 19 Aug 2004 19:06:10 +0000 (GMT) Received: from www.citello.it (host170-131.pool80117.interbusiness.it [80.117.131.170]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7F43743D2D for ; Thu, 19 Aug 2004 19:06:09 +0000 (GMT) (envelope-from molter@tin.it) Received: from gattaccio.codalunga (ANice-205-1-5-94.w81-53.abo.wanadoo.fr [81.53.76.94]) by www.citello.it (Postfix) with ESMTP id 9877015ED for ; Thu, 19 Aug 2004 21:06:07 +0200 (CEST) Received: by gattaccio.codalunga (Postfix, from userid 1001) id 3B85EC0E1; Thu, 19 Aug 2004 21:04:28 +0200 (CEST) Date: Thu, 19 Aug 2004 21:04:28 +0200 From: Marco Molteni To: hackers@freebsd.org Message-Id: <20040819210428.30f7cf1d.molter@tin.it> X-Mailer: Sylpheed version 0.9.12 (GTK+ 1.2.10; i386-portbld-freebsd5.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: remote kernel gdb: break, continue: fatal trap 12 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 19 Aug 2004 19:06:10 -0000 Hi, I am playing around with remote gdb on a -current cvsupped 2 days ago. In gdb I set a breakpoint on ums_open (USB mouse driver, as a module), in the console I execute cat /dev/ums0, the breakpoint triggers, in gdb I issue a continue and I get a Fatal trap 12: page fault while in kernel mode, as detailed below. Any ideas why? thanks marco (gdb) tr0 (gdb) getsyms [..] (gdb) b ums_open Breakpoint 1 at 0xc072eedf: file /home/usr.src/sys/modules/ums/../../dev/usb/ums.c, line 594. (gdb) c ================= cat /dev/ums0 ================= [New Thread 100057] [Switching to Thread 100057] Breakpoint 1, ums_open (dev=0xc064ef6c, flag=0x1, fmt=0x2000, p=0xc10242c0) at /home/usr.src/sys/modules/ums/../../dev/usb/ums.c:594 (gdb) c Program received signal SIGSEGV, Segmentation fault. cdevsw_rel (csw=0x0) at /home/usr.src/sys/kern/kern_conf.c:124 /home/usr.src/sys/kern/kern_conf.c:124:3280:beg:0xc0489e14 Fatal trap 12: page fault while in kernel mode fault virtual address = 0x48 fault code = supervisor write, page not present instruction pointer = 0x8:0xc0489e14 stack pointer = 0x10:0xcbf6e9c0 frame pointer = 0x10:0xcbf6e9c4 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 = 559 (cat) --