Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754073Ab0AQPDY (ORCPT ); Sun, 17 Jan 2010 10:03:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754047Ab0AQPDX (ORCPT ); Sun, 17 Jan 2010 10:03:23 -0500 Received: from casper.infradead.org ([85.118.1.10]:51719 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752847Ab0AQPDX convert rfc822-to-8bit (ORCPT ); Sun, 17 Jan 2010 10:03:23 -0500 Subject: Re: [RFC] [PATCH 1/7] User Space Breakpoint Assistance Layer (UBP) From: Peter Zijlstra To: Avi Kivity Cc: ananth@in.ibm.com, Jim Keniston , Srikar Dronamraju , Ingo Molnar , Arnaldo Carvalho de Melo , utrace-devel , Frederic Weisbecker , Masami Hiramatsu , Maneesh Soni , Mark Wielaard , LKML In-Reply-To: <4B5325CF.5000001@redhat.com> References: <20100111122521.22050.3654.sendpatchset@srikar.in.ibm.com> <20100111122529.22050.32596.sendpatchset@srikar.in.ibm.com> <1263467289.4244.288.camel@laptop> <1263498366.4875.25.camel@localhost.localdomain> <1263546228.4244.343.camel@laptop> <20100115093831.GC26396@in.ibm.com> <1263549014.4244.374.camel@laptop> <4B53213C.9050303@redhat.com> <1263739939.557.20938.camel@twins> <4B5325CF.5000001@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Sun, 17 Jan 2010 16:03:13 +0100 Message-ID: <1263740593.557.20967.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1370 Lines: 31 On Sun, 2010-01-17 at 16:59 +0200, Avi Kivity wrote: > On 01/17/2010 04:52 PM, Peter Zijlstra wrote: > > On Sun, 2010-01-17 at 16:39 +0200, Avi Kivity wrote: > > > >> On 01/15/2010 11:50 AM, Peter Zijlstra wrote: > >> > >>> As previously stated, I think poking at a process's address space is an > >>> utter no-go. > >>> > >>> > >> Why not reserve an address space range for this, somewhere near the top > >> of memory? It doesn't have to be populated if it isn't used. > >> > > Because I think poking at a process's address space like that is gross. > > Also, if its fixed size you're imposing artificial limits on the number > > of possible probes. > > > > btw, an alternative is to require the caller to provide the address > space for this. If the caller is in another process, we need to allow > it to play with the target's address space (i.e. mmap_process()). I > don't think uprobes justifies this by itself, but mmap_process() can be > very useful for sandboxing with seccomp. mmap_process() sounds utterly gross, one process playing with another process's address space.. yuck! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/