From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754952AbYIQOVM (ORCPT ); Wed, 17 Sep 2008 10:21:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752987AbYIQOU4 (ORCPT ); Wed, 17 Sep 2008 10:20:56 -0400 Received: from mailer1.option.com ([81.246.70.162]:57746 "EHLO mailer1.option.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752945AbYIQOU4 (ORCPT ); Wed, 17 Sep 2008 10:20:56 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AocBAGSv0EgKAAAZ/2dsb2JhbAAIuGqBZw Message-ID: <48D1122F.6080101@option.com> Date: Wed, 17 Sep 2008 16:20:31 +0200 From: Denis Joseph Barrow User-Agent: Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: Jason Wessel CC: "Amit S. Kale" , Tom Rini , David Grothe , Tigran Aivazian , linux-kernel@vger.kernel.org Subject: Re: getting false SIGTRAP breakpoints in kernel i.e. kernel hung unless gdb remotely attached on x86 & cont is issued References: <48D10A70.8050202@option.com> <48D10C43.90605@windriver.com> In-Reply-To: <48D10C43.90605@windriver.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 17 Sep 2008 14:20:31.0137 (UTC) FILETIME=[8A6C0910:01C918D0] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jason, The problem I believe is very reproducable. I'm doing nothing special with kgdb just using it to help me with 3g modem driver development & my driver wasn't loaded when the problem occured. I have the following command in my /boot/grub/menu.lst kernel parameter to enable gdb. kgdboc=/dev/ttyS0,115200 maxcpus=1 And when I do the steps mentioned when in a console I get a message waiting for gdb to attach I'm familiar with kgdb, have been using it for years & know enough to be sure this is undesired behaviour. Jason Wessel wrote: > Denis Joseph Barrow wrote: >> Hi ladies/gentlemen, >> The kernel I'm running gdb with is 2.6.27-rc4 >> The false sigtrap is occuring in ia32_sysenter_target in arch/x86/kernel/entry_32.S:303 >> when gdb is stepped from the user process as described below >> >> > > Your example does not indicate how or why you setup kgdb. kgdb can be > compiled into the kernel, but it should not have any effect what so ever > unless it is configured for use because it will not register to receive > any of the breakpoint or single stepping traps. > > Perhaps there is more to the description of your problem? > > Jason. > >> To reproduce >> compile kernel with kgdb support >> compile my randsleep program attached using the .mk script >> as root >> attach randsleep to an idle serial port e.g. /dev/ttyS0 by typing >> randsleep /dev/ttyS0 >> from another bash shell type >> ps -aux | grep randsleep >> >> gdb ./randsleep >> attach >> >> You should get messages from gdb like >> Attaching to program: /home/djbarrow/devel2/randsleep/randsleep, process 6397 >> Reading symbols from /lib/tls/i686/cmov/libc.so.6...done. >> Loaded symbols for /lib/tls/i686/cmov/libc.so.6 >> Reading symbols from /lib/ld-linux.so.2...done. >> Loaded symbols for /lib/ld-linux.so.2 >> 0xb7fda430 in __kernel_vsyscall () >> >> Now type step. >> >> The machine is now hung until gdb attaches remotely. >> >> >> -- best regards, D.J. Barrow