From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v2 1/3] bpf: Use 1<<16 as ceiling for immediate alignment in verifier. Date: Fri, 19 May 2017 19:16:15 -0400 (EDT) Message-ID: <20170519.191615.136362788931426782.davem@davemloft.net> References: <20170519.164154.368589666756458942.davem@davemloft.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: ecree@solarflare.com, daniel@iogearbox.net, alexei.starovoitov@gmail.com, netdev@vger.kernel.org To: ast@fb.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:59076 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751049AbdESXQT (ORCPT ); Fri, 19 May 2017 19:16:19 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: From: Alexei Starovoitov Date: Fri, 19 May 2017 14:37:56 -0700 > On 5/19/17 1:41 PM, David Miller wrote: >> From: Edward Cree >> Date: Fri, 19 May 2017 18:17:42 +0100 >> >>> One question: is there a way to build the verifier as userland code >>> (or at least as a module), or will I have to reboot every time I >>> want to test a change? >> >> There currently is no such machanism, you will have to reboot every >> time. >> >> I have considered working on making the code buildable outside of the >> kernel. It shouldn't be too hard. > > it's not hard. > We did it twice and both times abandoned. > First time to have 'user space verifier' to check programs before > loading and second time for fuzzing via llvm. > Abandoned since it diverges very quickly from kernel. > Well, my idea was the create an environment in which kernel verifier.c could be built as-is. Maybe there would be some small compromises in verifier.c such as an ifdef test or two, but that should be it. It really is just a piece of what amounts to compiler infrastructure and not very kernel specific.