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=-1.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 3B97FC282CE for ; Thu, 11 Apr 2019 03:13:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B2692133D for ; Thu, 11 Apr 2019 03:13:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=netronome-com.20150623.gappssmtp.com header.i=@netronome-com.20150623.gappssmtp.com header.b="j4PbWG9N" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726678AbfDKDNR (ORCPT ); Wed, 10 Apr 2019 23:13:17 -0400 Received: from mail-qk1-f194.google.com ([209.85.222.194]:36868 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725782AbfDKDNR (ORCPT ); Wed, 10 Apr 2019 23:13:17 -0400 Received: by mail-qk1-f194.google.com with SMTP id c1so2619505qkk.4 for ; Wed, 10 Apr 2019 20:13:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netronome-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :organization:mime-version:content-transfer-encoding; bh=/YEEa7TET5vphgSbGlr4PUnj23dJzPK+9Di7VW+9W70=; b=j4PbWG9NCg+wZyVLjyxwXhHj09YAHGhm5PM6OidzjQ4Xvox7lphxhRZWkz0paVKQxY AO7BPoxZchD5Rqlhp3tTbLLJaH0v87/gubTD2TG3kd11jpTSIL21kAVSm4QEoWG0FnJY 7Na+eEae7egm5O0Gs1MVczNMofmeHhUcgN1mgFs0oG4yvGZi7RXx0q9WFS3hkWO0tL7K PIBbI7dfBRFs3oRN5qqZXa35zlEZs7m6vjupW0m68ciexJjOiXzLrHc6+PbLQNGaNR3l 5lc6TU8ZTmKtjODVlg9fHbnMfGdmU8HJ4OGnri5Vu693i4R9UtV5eKsI7EpXVleszVfV Agfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:organization:mime-version:content-transfer-encoding; bh=/YEEa7TET5vphgSbGlr4PUnj23dJzPK+9Di7VW+9W70=; b=eGbdEMJuArRgp6tPn4rxDmCHaYI3+2OHb6JsTO2xXbBJQsuTP2oTfITAJuh8wN9Mf4 Jt8qTTTfDbRLc6EcAqZmIBODTdYaePdFnYw37yIDLxn2zB8t+VMtiWJupN81o402k8jS tq2jwlHsZdDIb09+tNe1kxBd7dqR3vbylUJ3tiiSKD+sNGUL2fBgFup3ca4A/VFHr3zz Uz3o1YiICqfSt63JwPrax3WHWJEpW+5SeYKrUGq05J8fZEj5DktoNYXzmbD/FhKTvQ0+ BDLhfhco000tXury78IRFoJKsh11WHVLagM8RiIKifJaIA4vS/0R2tBqHFQaXEJE4kP2 y+XQ== X-Gm-Message-State: APjAAAVeTmTuVEozSxbdx01CjPyQQJOU4P0qA3r4hq3VJraM6erdt7Vm lWZhbmcOA0ndW1kKhREPMH49+A== X-Google-Smtp-Source: APXvYqwTpE+0yGmPUJcI7YY8QE48R8x9FTnciMKGCCRLbDaRJf/NcACxSTCW2MOwfKPuTg3qGOPm4A== X-Received: by 2002:a37:e20e:: with SMTP id g14mr36499581qki.138.1554952396322; Wed, 10 Apr 2019 20:13:16 -0700 (PDT) Received: from cakuba.netronome.com ([66.60.152.14]) by smtp.gmail.com with ESMTPSA id r15sm25583749qtb.22.2019.04.10.20.13.15 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 10 Apr 2019 20:13:16 -0700 (PDT) Date: Wed, 10 Apr 2019 20:13:12 -0700 From: Jakub Kicinski To: Jiong Wang Cc: alexei.starovoitov@gmail.com, daniel@iogearbox.net, bpf@vger.kernel.org, netdev@vger.kernel.org, oss-drivers@netronome.com Subject: Re: [PATCH/RFC v2 bpf-next 06/19] bpf: mark lo32 writes that should be zero extended into hi32 Message-ID: <20190410201302.4e67d48f@cakuba.netronome.com> In-Reply-To: <1554925833-7333-7-git-send-email-jiong.wang@netronome.com> References: <1554925833-7333-1-git-send-email-jiong.wang@netronome.com> <1554925833-7333-7-git-send-email-jiong.wang@netronome.com> Organization: Netronome Systems, Ltd. MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, 10 Apr 2019 20:50:20 +0100, Jiong Wang wrote: > @@ -2169,6 +2188,12 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn > value_regno); > if (reg_type_may_be_null(reg_type)) > regs[value_regno].id = ++env->id_gen; > + /* A load of ctx field could have different > + * actual load size with the one encoded in the > + * insn. When the dst is PTR, it is for sure not > + * a sub-register. > + */ > + regs[value_regno].subreg_def = DEF_NOT_SUBREG; Can't the rewrite generate a 32bit load? E.g. reading skb->len will be LDX | W, we still gotta clear the top bits in that case, no? I can't find the explanation of this case with a quick scan of the code and cover letter.. > } > regs[value_regno].type = reg_type; > }