From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [PATCH net] bpf: don't select potentially stale ri->map from buggy xdp progs Date: Fri, 8 Sep 2017 07:06:10 +0200 Message-ID: <20170908070610.4b8e1df1@redhat.com> References: <01d69254802986ad3a8b18a8650c45df3df95def.1504821825.git.daniel@iogearbox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, ast@fb.com, john.fastabend@gmail.com, andy@greyhouse.net, netdev@vger.kernel.org, brouer@redhat.com To: Daniel Borkmann Return-path: Received: from mx1.redhat.com ([209.132.183.28]:45944 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751088AbdIHFGR (ORCPT ); Fri, 8 Sep 2017 01:06:17 -0400 In-Reply-To: <01d69254802986ad3a8b18a8650c45df3df95def.1504821825.git.daniel@iogearbox.net> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 8 Sep 2017 00:14:51 +0200 Daniel Borkmann wrote: > + /* This is really only caused by a deliberately crappy > + * BPF program, normally we would never hit that case, > + * so no need to inform someone via tracepoints either, > + * just bail out. > + */ > + if (unlikely(map_owner != xdp_prog)) > + return -EINVAL; IMHO we do need to call the tracepoint here. It is not just crappy BPF-progs that cause this situation, it is also drivers not implementing XDP_REDIRECT yet (which is all but ixgbe). Due to the level XDP operates at, tracepoints are the only way users can runtime troubleshoot their XDP programs. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer