From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5141 invoked by alias); 12 Aug 2010 23:55:17 -0000 Mailing-List: contact archer-help@sourceware.org; run by ezmlm Sender: Precedence: bulk List-Post: List-Help: List-Subscribe: List-Id: Received: (qmail 5129 invoked by uid 22791); 12 Aug 2010 23:55:16 -0000 X-SWARE-Spam-Status: No, hits=-6.7 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Date: Thu, 12 Aug 2010 23:55:00 -0000 From: Oleg Nesterov To: Tom Tromey Cc: archer@sourceware.org, utrace-devel@redhat.com Subject: problems with v3 (Was: gdbstub initial code, v3) Message-ID: <20100812235228.GA15051@redhat.com> References: <20100811235810.GA9783@redhat.com> <20100812011113.GA13212@redhat.com> <20100812023750.GA17011@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-SW-Source: 2010-q3/txt/msg00101.txt.bz2 On 08/11, Tom Tromey wrote: > > >>>>> "Oleg" == Oleg Nesterov writes: > > Oleg> So, the patch below fixes the problem, and gdb + /proc/ugdb seems > Oleg> to work. > > Oleg> Indeed, gdb sees that this fd is not pipe/tcp and uses the "hardwire" > Oleg> serial_ops, but hardwire_readchar() doesn't play well with select(). > > Oleg> Please teach gdb to use poll/select ? > > I looked at this a little bit. It seems to me that the "hardwire" stuff > is for talking to ttys, and we instead want gdb to be using the pipe code. I didn't verify this, but I don't think so. Please look at pipe_open(). Perhaps it makes sense to serial_add_interface("ugdb"), I dunno. OK. I was going to add some cleanups and send the new version today. But after some testing (without gdb) I hit the kernel crashes. This makes me think that probably something is wrong ;) As usual, I can't blame my code. I am still investigating, the crash is not easy to reproduce, but so far I _suspect_ the problems in utrace code. At least utrace_barrier()->signal_pending() is definitely not right. Will continue tomorrow. Oleg.