From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [bpf-next PATCH 3/3] bpf: add sample program to trace map events Date: Mon, 23 Apr 2018 22:22:38 +0200 Message-ID: <20180423222238.2636bdc8@redhat.com> References: <152406544226.3465.948692097697975172.stgit@localhost.localdomain> <152406545918.3465.14253635905960610284.stgit@localhost.localdomain> <20180420002735.ytmnhzs73rwkwewm@ast-mbp> <20180420114711.1a06fb26@redhat.com> <062780b1-6a24-a7f3-175c-db3b02605850@polito.it> <20180423200801.m2kcrjcoavuibbmk@ast-mbp> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Sebastiano Miano , netdev@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, mingo@redhat.com, rostedt@goodmis.org, fulvio.risso@polito.it, "David S. Miller" , brouer@redhat.com To: Alexei Starovoitov Return-path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:37752 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932434AbeDWUWn (ORCPT ); Mon, 23 Apr 2018 16:22:43 -0400 In-Reply-To: <20180423200801.m2kcrjcoavuibbmk@ast-mbp> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 23 Apr 2018 14:08:02 -0600 Alexei Starovoitov wrote: > On Mon, Apr 23, 2018 at 04:08:36PM +0200, Sebastiano Miano wrote: > > > > That's in fact the real use case for the first two patches. Since bpf > > tracepoints are still a rather common (and easy to use) troubleshooting and > > monitoring tool why shouldn't we "enhance" their support with the newly > > added map/prog IDs? > > because these tracepoints can be abused in the way that this patch demonstrated. > Whether to keep this patch in the series or not is irrelevant. I don't understand your abuse use-case, can you explain what you mean? You do realize that these tracepoints can _only_ monitor the userspace map activity (not kernel map changes) ... and we _do_ need a way to debug this (and without the map_id I can tell which map). -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer