From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E87DC433E5 for ; Tue, 28 Jul 2020 21:33:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 540F62070A for ; Tue, 28 Jul 2020 21:33:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729520AbgG1VdQ (ORCPT ); Tue, 28 Jul 2020 17:33:16 -0400 Received: from www62.your-server.de ([213.133.104.62]:36118 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729243AbgG1VdQ (ORCPT ); Tue, 28 Jul 2020 17:33:16 -0400 Received: from sslproxy01.your-server.de ([78.46.139.224]) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1k0XDl-0005Yp-GD; Tue, 28 Jul 2020 23:33:13 +0200 Received: from [178.196.57.75] (helo=pc-9.home) by sslproxy01.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1k0XDl-000FAD-AU; Tue, 28 Jul 2020 23:33:13 +0200 Subject: Re: [PATCH v5 bpf-next 4/6] bpf, x64: rework pro/epilogue and tailcall handling in JIT To: Maciej Fijalkowski , ast@kernel.org Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, bjorn.topel@intel.com, magnus.karlsson@intel.com References: <20200724173557.5764-1-maciej.fijalkowski@intel.com> <20200724173557.5764-5-maciej.fijalkowski@intel.com> From: Daniel Borkmann Message-ID: <38407b6c-12a2-671f-9929-2ef39be62542@iogearbox.net> Date: Tue, 28 Jul 2020 23:33:12 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20200724173557.5764-5-maciej.fijalkowski@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.102.3/25887/Tue Jul 28 17:44:20 2020) Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 7/24/20 7:35 PM, Maciej Fijalkowski wrote: > This commit serves two things: > 1) it optimizes BPF prologue/epilogue generation > 2) it makes possible to have tailcalls within BPF subprogram [...] [...] > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c > index 7be02e555ab9..d86a35474d7b 100644 > --- a/kernel/bpf/core.c > +++ b/kernel/bpf/core.c > @@ -773,7 +773,8 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, > > if (size > poke_tab_max) > return -ENOSPC; > - if (poke->ip || poke->ip_stable || poke->adj_off) > + if (poke->tailcall_target || poke->tailcall_target_stable || > + poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) > return -EINVAL; Hmm, I thought we've been through this from prior review rounds, but these sort of changes break bisectability. You've already renamed the whole thing in patch 3/6 (poke->ip and the poke->ip_stable). So if you've applied up to patch 3, then build breaks right here. > switch (poke->reason) { >