Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932417Ab0AOXoz (ORCPT ); Fri, 15 Jan 2010 18:44:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932409Ab0AOXox (ORCPT ); Fri, 15 Jan 2010 18:44:53 -0500 Received: from e36.co.us.ibm.com ([32.97.110.154]:60306 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932381Ab0AOXow (ORCPT ); Fri, 15 Jan 2010 18:44:52 -0500 Subject: Re: [RFC] [PATCH 4/7] Uprobes Implementation From: Jim Keniston To: Peter Zijlstra Cc: maneesh@in.ibm.com, Srikar Dronamraju , Ingo Molnar , Arnaldo Carvalho de Melo , Ananth N Mavinakayanahalli , utrace-devel , Mark Wielaard , Frederic Weisbecker , Masami Hiramatsu , LKML In-Reply-To: <1263553955.4244.393.camel@laptop> References: <20100111122521.22050.3654.sendpatchset@srikar.in.ibm.com> <20100111122553.22050.46895.sendpatchset@srikar.in.ibm.com> <1263467394.4244.291.camel@laptop> <1263509380.4875.35.camel@localhost.localdomain> <1263546632.4244.352.camel@laptop> <20100115102645.GA22640@linux.vnet.ibm.com> <1263551607.4244.379.camel@laptop> <20100115110547.GB3660@in.ibm.com> <1263553955.4244.393.camel@laptop> Content-Type: text/plain Date: Fri, 15 Jan 2010 15:44:45 -0800 Message-Id: <1263599085.5007.88.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 (2.12.3-8.el5_2.3) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2010-01-15 at 12:12 +0100, Peter Zijlstra wrote: ... > > Adding the probe uses the fact that (most) executable mappings are > MAP_PRIVATE and CoWs a private copy of the page with the modified ins, > right? > > What does it do for MAP_SHARED|MAP_EXECUTABLE sections -- simply fail to > add the probe? If the vma containing the instruction to be probed has the VM_EXEC flag set (and it's not in the XOL area) we go ahead and try to probe it. I'm not familar with the implications of MAP_SHARED|MAP_EXECUTABLE -- how you would get such a combo, or what access_process_vm() would do with it. Jim -- 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/