From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4882 invoked by alias); 13 Aug 2012 13:20:29 -0000 Received: (qmail 4869 invoked by uid 22791); 13 Aug 2012 13:20:26 -0000 X-SWARE-Spam-Status: No, hits=-6.1 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,RCVD_IN_DNSWL_HI,RCVD_IN_HOSTKARMA_W,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 13 Aug 2012 13:20:08 +0000 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q7DDJeUO009182 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 13 Aug 2012 09:19:40 -0400 Received: from tranklukator.brq.redhat.com (dhcp-1-232.brq.redhat.com [10.34.1.232]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id q7DDJaA4000342; Mon, 13 Aug 2012 09:19:37 -0400 Received: by tranklukator.brq.redhat.com (nbSMTP-1.00) for uid 500 oleg@redhat.com; Mon, 13 Aug 2012 15:16:27 +0200 (CEST) Date: Mon, 13 Aug 2012 13:20:00 -0000 From: Oleg Nesterov To: Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Peter Zijlstra , Arnaldo Carvalho de Melo , Roland McGrath , Srikar Dronamraju , Ananth N Mavinakaynahalli , stan_shebs@mentor.com, gdb-patches@sourceware.org Subject: Re: [RFC 5/5] uprobes: add global breakpoints Message-ID: <20120813131623.GA5269@redhat.com> References: <1344355952-2382-1-git-send-email-bigeasy@linutronix.de> <1344355952-2382-6-git-send-email-bigeasy@linutronix.de> <20120808131457.GA5309@redhat.com> <20120809171802.GB27835@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120809171802.GB27835@linutronix.de> User-Agent: Mutt/1.5.18 (2008-05-17) Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-08/txt/msg00358.txt.bz2 On 08/09, Sebastian Andrzej Siewior wrote: > > * Oleg Nesterov | 2012-08-08 15:14:57 [+0200]: > > >> What I miss right now is an interface to tell the user/gdb that there is a > >> program that hit a global breakpoint and is waiting for further instructions. > >> A "tail -f trace" does not work and may contain also a lot of other > >> informations. I've been thinking about a poll()able file which returns pids of > >> tasks which are put on hold. Other suggestions? > > > >Honestly, I am not sure this is that useful... > > How would you notify gdb that there is a new task that hit a breakpoint? > Or learn yourself? But why do we need this? OK, you do not need to convince me, I try to never argue with new features. However, I certainly dislike TASK_TRACED in uprobe_wait_traced(). And sleeping in ->handler() is not fair to other consumers. And I do not think you should modify ptrace_attach() at all. gdb/user can wakeup the task after PTRACE_ATTACH itself. Oleg.