From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262910AbUBZSJO (ORCPT ); Thu, 26 Feb 2004 13:09:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262844AbUBZSJO (ORCPT ); Thu, 26 Feb 2004 13:09:14 -0500 Received: from fed1mtao01.cox.net ([68.6.19.244]:3732 "EHLO fed1mtao01.cox.net") by vger.kernel.org with ESMTP id S262917AbUBZSIU (ORCPT ); Thu, 26 Feb 2004 13:08:20 -0500 Date: Thu, 26 Feb 2004 11:08:18 -0700 From: Tom Rini To: "Amit S. Kale" Cc: kernel list , Pavel Machek , kgdb-bugreport@lists.sourceforge.net Subject: Re: [Kgdb-bugreport] [PATCH][3/3] Update CVS KGDB's wrt connect / detach Message-ID: <20040226180818.GU1052@smtp.west.cox.net> References: <20040225213626.GF1052@smtp.west.cox.net> <20040225214343.GG1052@smtp.west.cox.net> <20040225215309.GI1052@smtp.west.cox.net> <200402261344.49261.amitkale@emsyssoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200402261344.49261.amitkale@emsyssoft.com> User-Agent: Mutt/1.5.5.1+cvs20040105i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 26, 2004 at 01:44:49PM +0530, Amit S. Kale wrote: > On Thursday 26 Feb 2004 3:23 am, Tom Rini wrote: > > The following patch fixes a number of little issues here and there, and > > ends up making things more robust. > > - We don't need kgdb_might_be_resumed or kgdb_killed_or_detached. > > GDB attaching is GDB attaching, we haven't preserved any of the > > previous context anyhow. > > If gdb is restarted, kgdb has to remove all breakpoints. Present kgdb does > that in the code this patch removes: OK. After talking with Daniel Jacobowitz abit about this, the '?' packet will only be sent once per session. So this is how we have to deal with disconnect / gdb dying. I'll re-work the patch a bit to reflect this. > > - Don't try and look for a connection in put_packet, after we've tried > > to put a packet. Instead, when we receive a packet, GDB has > > connected. > > We have to check for gdb connection in putpacket or else following problem > occurs. > > 1. kgdb console messages are to be put. > 2. gdb dies > 3. putpacket writes the packet and waits for a '+' > 4. new gdb sends a protocol initialization packet > 5. putpacket reads characters in that packet hoping for an incoming '+' > sending out console message packet on each incoming character > 6. gdb receives and rejects each console message packet How about something like the following: putpacket(msg) { if (!kgdb_connected) return; /* No one wants this */ do { /* Write out $pack#checksum */ ch = kgdb_get_debug_char(); if (ch == '+' /* ACK */ || ch == '$' /* Packet before an ACK? must be a reattach. */ ) return; } } With the suggested change for the ? packet, we quickly get to the point where we're back in kgdb_handle_exception() and will know this is a restart shortly. -- Tom Rini http://gate.crashing.org/~trini/