From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759307AbYGQNWU (ORCPT ); Thu, 17 Jul 2008 09:22:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756070AbYGQNWH (ORCPT ); Thu, 17 Jul 2008 09:22:07 -0400 Received: from fk-out-0910.google.com ([209.85.128.189]:37973 "EHLO fk-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756177AbYGQNWF (ORCPT ); Thu, 17 Jul 2008 09:22:05 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=sEz164h6l/s37Hlvxqj9AHJiPPVDMAyIyTcI+mIpjiVkVm2sgGeEkuCISYqzhFrD7s qlVlg1qJs+r0wR3i/6xaYFhalJ5LK9WZ7AET3wklC/tkiLPqMBFIlhIBJPwcYlBjcsaN nRz/XsUA/wlbg/Uzfqry28Ycac6sumO1KA4fE= Subject: Re: Usage of kgdb in v2.6.26 From: ZC Miao To: Jason Wessel Cc: Linux Kernel In-Reply-To: <487F45B8.4010708@windriver.com> References: <1216245603.3664.29.camel@hellwolf-sony.freehell.org> <487F45B8.4010708@windriver.com> Content-Type: text/plain Date: Thu, 17 Jul 2008 14:21:47 +0100 Message-Id: <1216300907.3905.2.camel@hellwolf-sony.freehell.org> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 (2.22.3.1-1.fc9) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org $ cat ../../output/x86.kerneldev/.config| grep CONFIG_DEBUG_RODATA CONFIG_DEBUG_RODATA=y Yes, conigured. On Thu, 2008-07-17 at 08:14 -0500, Jason Wessel wrote: > > Do you have CONFIG_DEBUG_RODATA=y in your kernel config? > > There is a presently a known problem where breakpoints will silently > fail to plant when this is turned on. > > Jason. > > ZC Miao wrote: > > I tried to use the kgdb from v2.6.26, but met few problems. > > I use : > > 1. gdb 6.8 (gdb-6.8-11.fc9.i386) > > 2. kernel v2.6.26 source code > > 3. Qemu 0.9.1 (qemu-0.9.1-5.fc9.i386) > > 4. Host is : 2.6.25.10-86.fc9.i686 > > 5. Cpu : Intel(R) Core(TM)2 Duo CPU T5450 @ 1.66GHz > > > > > > * Firstly I compile kernel 2.6.26 with kgdb support : > > CONFIG_KGDB=y > > CONFIG_KGDB_SERIAL_CONSOLE=y > > > > * Then I use qemu to boot my kernel along with a rootfs that I created, > > with a qemu option that makes a local tcp port a listening service as a > > serial port for the emulated system. The kernel arguments I gave is : > > nfsroot=192.168.200.1:/path/to/rootfs,udp,nolock ip=dhcp root=/dev/nfs > > ro single kgdboc=ttyS0,115200 kgdbwait > > > > * After the kernel loaded and boot for a while, the gdb receives a > > signal and hangs the kernel : > > kgdb_register_io_module (new_kgdb_io_ops=) > > at /data/home/hellwolf/mydoc/prog/linux/linux-2.6/kernel/kgdb.c:1674 > > (gdb) > > > > Question 1 : > > * If I type "b sys_read", and then "c", the kernel continues until I > > get : > > > > --------------------------------------------------------------- > > [New Thread 1] > > Cannot remove breakpoints because program is no longer writable. > > It might be running in another process. > > Further execution is probably impossible. > > > > Breakpoint 1, sys_read (fd=3, buf=0xbfdb31dc "", count=512) > > > > at /data/home/hellwolf/mydoc/prog/linux/linux-2.6/fs/read_write.c:360 > > (gdb) > > --------------------------------------------------------------- > > > > Why "program is no longer writable" happens here? > > > > Question 2 : > > * If I directly type "c" when kgdbwait triggered. And use Sys-Rq+G to > > interrupt the kernel, I will get : > > --------------------------------------------------------------- > > [New Thread -1] > > > > Program received signal SIGTRAP, Trace/breakpoint trap. > > [Switching to Thread -1] > > sysrq_handle_gdb (key=103, tty=0xc78f6400) > > at /data/home/hellwolf/mydoc/prog/linux/linux-2.6/kernel/kgdb.c:167 > > (gdb) > > --------------------------------------------------------------- > > Here if I type "c sys_read" and "c", it never actually makes any break > > points, I will never receive a break from gdb. > > > > > > I don't know if I made anything wrong, or I missed any important thing, > > so I post here and would like to get some help from you. > > > > Thanks. > > > > -- > > ZC Miao (hellwolf.misty@gmail.com) > > Blog http://hellwolf.cublog.cn > > > > gpg --keyserver pgp.mit.edu --recv-key 0x6B174C6F > > > > Most people deserve each other. > > -- Shirley > > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > > > -- ZC Miao (hellwolf.misty@gmail.com) Blog http://hellwolf.cublog.cn gpg --keyserver pgp.mit.edu --recv-key 0x6B174C6F Regarding astral projection, Woody Allen once wrote, "This is not a bad way to travel, although there is usually a half-hour wait for luggage."