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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B65ABC433FE for ; Fri, 20 May 2022 22:47:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353957AbiETWq6 (ORCPT ); Fri, 20 May 2022 18:46:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58468 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231520AbiETWq5 (ORCPT ); Fri, 20 May 2022 18:46:57 -0400 Received: from mail-ej1-x62a.google.com (mail-ej1-x62a.google.com [IPv6:2a00:1450:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE2A8AFAE0; Fri, 20 May 2022 15:46:55 -0700 (PDT) Received: by mail-ej1-x62a.google.com with SMTP id gi33so9566628ejc.3; Fri, 20 May 2022 15:46:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=7VSmTsrf2yRmDPUJj7O4mhbeh8I71iXxthfFzi3aXkY=; b=IDKxeJ8SiDdIfH863/nqT0j9/oK9RffxHSoBU/YfUbDXzroET4eYNRV1zNCUxEaWnG Pkot+DctHiLZHSYTz17WCwyNwWLNSzhphRyOXbp7mEMH/Oc3vAfXrQ7e9HjTaV7CeG68 SHLv0AIKUUdwf0seJRCjZgNvM1AHSlgRsgPwxlwX3l88C+2TFL4lU1u5IpyhxM57s0hb 03acGg740tRQaowRW+Qs5heTK3Es+GTTDJwJ5faZBiF9W2eDzTMOQUCymSVSElXBl31R jUbpANF3T8Nh0O1Hn1TbalyTbIiNMo0UengQkfo8Nc1gsWFK5p3LNP53QTP5oOKsFJ/k XMNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=7VSmTsrf2yRmDPUJj7O4mhbeh8I71iXxthfFzi3aXkY=; b=LU3yUXwmc/+eNNtxI9XRQfwdD41o6Vd9RE4k8pX2gNN57d4Sezz+l/naTpP1qVlMzE ZQE+63rW+mDR3AY/6S+tqsn3dvyT5LfaySIrfoUPXQU2kK3SNDpSE5wX+ZtcZL9ZyzFM yD0VOxwkE8WfMRIEwjubzuBPS0bgvuddaxqVGC0fjtV6QFsYu8vBGMDMpqjOC2eJlaw5 UStAG1GxX3YYdep+Dui6C+i4IlLCUZtrLOpQ/yea9XGDLpv71ujDx37UvEjiE2LN3AgJ Gr4cjEl4Qs6T7Iy07mTkI88pbtL4kesch8MxnCTn9M2HCsUZlLeO57RD2rRwRp404OjU mWFw== X-Gm-Message-State: AOAM532g+01YLCZr/zZd31jrTDghvLKDg2QjsaLW3b4LnYgvmTpIyZYG z4UGWMXOSviUUAhehnvmNUVymkDKUclXkJZaGCI= X-Google-Smtp-Source: ABdhPJzv2U16Vzaku4966umMnfoPWOcUFGVy3bm7ySb9ND5HlqxVQMQuqiT4pmFn9OVXCr91+j9mXw9nQIm8v9wjJe8= X-Received: by 2002:a17:906:9753:b0:6fe:aafb:31a6 with SMTP id o19-20020a170906975300b006feaafb31a6mr4663290ejy.502.1653086814409; Fri, 20 May 2022 15:46:54 -0700 (PDT) MIME-Version: 1.0 References: <20220520113728.12708-1-shung-hsi.yu@suse.com> <20220520113728.12708-4-shung-hsi.yu@suse.com> In-Reply-To: <20220520113728.12708-4-shung-hsi.yu@suse.com> From: Alexei Starovoitov Date: Fri, 20 May 2022 15:46:40 -0700 Message-ID: Subject: Re: [PATCH bpf-next 3/4] bpf: verifier: remove redundant opcode checks To: Shung-Hsi Yu Cc: Network Development , bpf , LKML , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 20, 2022 at 4:38 AM Shung-Hsi Yu wrote: > > The introduction of opcode validation with bpf_opcode_in_insntable() in > commit 5e581dad4fec ("bpf: make unknown opcode handling more robust") > has made opcode checks done in do_check_common() and its callees > redundant, so either remove them entirely, or turn them into comments in > places where the redundancy may not be clear. I prefer to keep the existing checks. They help readability on what is actually expected at this point. These checks cost close to nothing in run-time.