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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 190E8C433F5 for ; Tue, 21 Sep 2021 03:25:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F28A761159 for ; Tue, 21 Sep 2021 03:25:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232378AbhIUD0o (ORCPT ); Mon, 20 Sep 2021 23:26:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352137AbhIUClV (ORCPT ); Mon, 20 Sep 2021 22:41:21 -0400 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 774E3C0613DE for ; Mon, 20 Sep 2021 19:32:37 -0700 (PDT) Received: by mail-pj1-x102f.google.com with SMTP id z14-20020a17090a8b8e00b0019cc29ceef1so906888pjn.1 for ; Mon, 20 Sep 2021 19:32:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Kh9m4MsiS5aI2YIIkSc7q5nTUFUakrir8LRIIqVUNec=; b=Wk0DGPRtV9aFleftAiyyoOdH1EdwsyP4fwPNPCzbT8Ucs/Tvmj379NjXAU7E6NGDJN H5CSmVObGptPI0ivz+G+pRMrWy06hhikY77FGYMpmOy+eQLbI4i0ut1w2guhUYRyhK1E CT3aRnkF20s9FDWigHhDtfssDZcCDIWjV2zgTJ3EnxqksCV6gbsqFGUW4rxhWdRExF62 ++RdnTYZ+pglknIFbIsa3y+tO9VE9xHt31MjFE1qB1ofGZFOorDVR9mI8Z4VYY2ssrPs Y47/Nnd7BPE9uhtTP6wq43fUfs7zStFcdvRHg19+Cv9VfR+ml8AL5ojR2dXtj1eufRyT 2V2g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=Kh9m4MsiS5aI2YIIkSc7q5nTUFUakrir8LRIIqVUNec=; b=rCJq1okTePtI25keIP11D5+HG/3HsxArDt9YoCbAPejkXjLkueMaIBJFdh+Dy3O++M CwNCT/GfB3cye55a6P9cR1E95b3QQoZnbWP9w32zBaxanXfZ3KIthgJLZtjsf311WTm6 jbPMiIEAxSVrUwQTNktlCiGJ+tA2g0n4TJmBiuiRT0YbGQMuuDxuiSjrWQrFSDOT8HIW FB846UqaC5mMY1Sbf/xsdIyaRyLIe5rxooMwq4SNxTJ6BLpl1IUIi2k1yqYC0GT+gmkQ WN9yl+FBNbQ58YhxdO89xf1CwvRSpulGxXVm5fFIO6VyLpYeawl1zJ/uQT3grZ0c4qET rNfA== X-Gm-Message-State: AOAM5319jhB1OACfYGgl+hsGwC9Vp+DJNtbaISfI0+2zS1RujbmW0QZ8 3uO/P/7YErpofssNB7fSdUwDREyBTKs= X-Google-Smtp-Source: ABdhPJwOQXMO44hgiyNrJoKo9lAr8TxDvL5PGwbadBLGgY6jPjZNaZfIm1mTAfCvMugKO6/hQCMeKQ== X-Received: by 2002:a17:902:d202:b0:13a:709b:dfb0 with SMTP id t2-20020a170902d20200b0013a709bdfb0mr25550666ply.34.1632191556751; Mon, 20 Sep 2021 19:32:36 -0700 (PDT) Received: from ast-mbp ([2620:10d:c090:400::5:e78f]) by smtp.gmail.com with ESMTPSA id a4sm625683pjd.48.2021.09.20.19.32.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Sep 2021 19:32:36 -0700 (PDT) Date: Mon, 20 Sep 2021 19:32:34 -0700 From: Alexei Starovoitov To: Martin KaFai Lau Cc: bpf@vger.kernel.org, Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Yonghong Song Subject: Re: [PATCH bpf-next 3/4] bpf: selftest: A bpf prog that has a 32bit scalar spill Message-ID: <20210921023234.pjnby3s4q4o4agwe@ast-mbp> References: <20210921013102.1035356-1-kafai@fb.com> <20210921013122.1037548-1-kafai@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210921013122.1037548-1-kafai@fb.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Mon, Sep 20, 2021 at 06:31:22PM -0700, Martin KaFai Lau wrote: > It is a simplified example that can trigger a 32bit scalar spill. > The const scalar is refilled and added to a skb->data later. > Since the reg state of the 32bit scalar spill is not saved now, > adding the refilled reg to skb->data and then comparing it with > skb->data_end cannot verify the skb->data access. > > With the earlier verifier patch and the llvm patch [1]. The verifier > can correctly verify the bpf prog. Let's land llvm patch and wait until CI picks up the new llvm build? Please add a comment to selftests/bpf/README.rst that describes the failing test when llvm is old. I'm guessing there is no easier way to reliably skip the test in such situation, since failure to load might be the result of some future changes. llvm version check won't work either. the patch 2 looks correct to me. I couldn't spot any issue with the logic.