From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2821 invoked by alias); 27 Jan 2003 21:02:29 -0000 Mailing-List: contact gdb-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sources.redhat.com Received: (qmail 2813 invoked from network); 27 Jan 2003 21:02:29 -0000 Received: from unknown (HELO crack.them.org) (65.125.64.184) by 172.16.49.205 with SMTP; 27 Jan 2003 21:02:29 -0000 Received: from nevyn.them.org ([66.93.61.169] ident=mail) by crack.them.org with asmtp (Exim 3.12 #1 (Debian)) id 18dIHd-0003to-00; Mon, 27 Jan 2003 17:03:17 -0600 Received: from drow by nevyn.them.org with local (Exim 3.36 #1 (Debian)) id 18dGP8-0003lo-00; Mon, 27 Jan 2003 16:02:54 -0500 Date: Mon, 27 Jan 2003 21:02:00 -0000 From: Daniel Jacobowitz To: "Bennett F. Dill" Cc: gdb@sources.redhat.com Subject: Re: core while attached Message-ID: <20030127210254.GA14418@nevyn.them.org> Mail-Followup-To: "Bennett F. Dill" , gdb@sources.redhat.com References: <20030127183252.GA9690@linux.dillfamily.org> <20030127191930.GB11567@nevyn.them.org> <20030127205815.GA10206@linux.dillfamily.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030127205815.GA10206@linux.dillfamily.org> User-Agent: Mutt/1.5.1i X-SW-Source: 2003-01/txt/msg00449.txt.bz2 On Mon, Jan 27, 2003 at 03:58:15PM -0500, Bennett F. Dill wrote: > On Mon, Jan 27, 2003 at 02:19:30PM -0500, Daniel Jacobowitz wrote: > > On Mon, Jan 27, 2003 at 01:32:52PM -0500, Bennett F. Dill wrote: > > > I hope that someone out there has the patience to look at my problem :-) > > > > > > Hi, I'm working with gdb and I have the -g option on my application. > > > Typically I get very descriptive error messages. This latest problem > > > however is really interesting though... It seems to be a problem with > > > libc.so.1... > > > > > > [history] > > > Anyway, the application runs in the background and is a server to about > > > 25 clients concurrently. It takes a few hours for the app to sigsegv. > > > Now, it never dumped a core for some reason, so i just attach gdb to the > > > process and continue and wait for the error to rear its head. Now, > > > since the app serves ~25 people, I don't really have time to look around > > > with the debugger... (I'm new to gdb, noo suprise I'm sure) > > > [/history] > > > > > > So my question is, is it possible to have the gdb that is attached to a > > > running process that has hit a signal sigsegv, to dump a core? This > > > way I can leisurly mull over the data. > > > > You're in luck. Grab a recent version of GDB and use the > > "generate-core-file" command. > > > > > More questions I have (totally n00bishness I'm sure), is how can I > > > find out what line of code in my app, called the 'deadly' function in > > > libc.so.1 (fprintf) and is there any way to view the call to fprintf > > > based on the memory address? > > > > > > Below is what I get from a where or a BT etc... If I try to use a > > > 'return' I go no where real fast. > > > > > > TIA for your assistance :-) > > > Ben > > > > > > > > > > > > Program received signal SIGSEGV, Segmentation fault. > > > 0xff30ceb8 in _getorientation () from /usr/lib/libc.so.1 > > > (gdb) where > > > #0 0xff30ceb8 in _getorientation () from /usr/lib/libc.so.1 > > > #1 0xff30d0dc in _set_orientation_byte () from /usr/lib/libc.so.1 > > > #2 0xff300710 in fprintf () from /usr/lib/libc.so.1 > > > #3 0x3aa80 in ?? () > > > #4 0x30420 in ?? () > > > #5 0x2f6f0 in ?? () > > > #6 0x2c7c8 in ?? () > > > #7 0x2c258 in ?? () > > > (gdb) > > > > That really looks like you're missing debug info; I don't know if those > > are legitimate code addresses on your platform or not. > > > > -- > > Daniel Jacobowitz > > MontaVista Software Debian GNU/Linux Developer > I'm ready to ask for a new version of gdb (5.3 is the latest i see), but > I don't see any documentation on generate-core-file anywhere... Before > I ask for a new version, can someone verify that generate-core-file is > the correct syntax/command? All I see is how to switch core files > etc... For whatever reason, it never made it into the manual. It's there; check the command-prompt help. (gdb) help generate-core-file Save a core file with the current state of the debugged process. Argument is optional filename. Default filename is 'core.'. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer