From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gdb-return-27558-listarch-gdb=sources.redhat.com@sourceware.org>
Received: (qmail 819 invoked by alias); 24 Jan 2007 12:48:33 -0000
Received: (qmail 513 invoked by uid 22791); 24 Jan 2007 12:48:31 -0000
X-Spam-Check-By: sourceware.org
Received: from nz-out-0506.google.com (HELO nz-out-0506.google.com) (64.233.162.235)     by sourceware.org (qpsmtpd/0.31) with ESMTP; Wed, 24 Jan 2007 12:48:24 +0000
Received: by nz-out-0506.google.com with SMTP id m7so141586nzf         for <gdb@sourceware.org>; Wed, 24 Jan 2007 04:48:22 -0800 (PST)
Received: by 10.65.241.20 with SMTP id t20mr1054073qbr.1169642902702;         Wed, 24 Jan 2007 04:48:22 -0800 (PST)
Received: from ?192.168.132.167? ( [222.66.14.54])         by mx.google.com with ESMTP id j4sm648254nzd.2007.01.24.04.48.20;         Wed, 24 Jan 2007 04:48:21 -0800 (PST)
Message-ID: <45B75585.2030900@gmail.com>
Date: Wed, 24 Jan 2007 12:48:00 -0000
From: Bin Chen <binary.chen@gmail.com>
User-Agent: Thunderbird 1.5.0.8 (X11/20061116)
MIME-Version: 1.0
To:  gdb@sourceware.org
Subject: attach gdbserver to itself
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
X-IsSubscribed: yes
Mailing-List: contact gdb-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <gdb.sourceware.org>
List-Subscribe: <mailto:gdb-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/gdb/>
List-Post: <mailto:gdb@sourceware.org>
List-Help: <mailto:gdb-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: gdb-owner@sourceware.org
X-SW-Source: 2007-01/txt/msg00306.txt.bz2

Hi,

Current I am doing a trick that attach the gdbserver to itself when the 
process encounter the segment fault, like this:

void segv_handler(int no)
{
    int pid, status;

    VoIPLog("segv_handler.");
    char buf[128];

    pid = getpid();

    sprintf(buf, "/usr/bin/gdbserver :9988 --attach %d", pid);

    pid = fork();
    if (pid == 0) {
        system(buf);
    } else
        ::wait((int *)&status);

    return;
}

But in most of time this can't get useful information, especially in 
multi threading env, most of time the result is wrong, of course, I am 
saying the backtrace.

But if I start program by gdbserver :9988 program, it can catch the 
error. What is the difference? How can I revise my code to make above 
code has same effect like starting the program by gdbserver?

I am debugging in ARM platform.

Any help appreciated!

Bin Chen