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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 AEB89C04AB1 for ; Mon, 13 May 2019 17:52:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A6A020873 for ; Mon, 13 May 2019 17:52:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Udd90F4h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731903AbfEMRwR (ORCPT ); Mon, 13 May 2019 13:52:17 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:42995 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731830AbfEMRwR (ORCPT ); Mon, 13 May 2019 13:52:17 -0400 Received: by mail-pf1-f196.google.com with SMTP id 13so7587559pfw.9; Mon, 13 May 2019 10:52:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=gG0BeH3aPQX6+9LO5Ic0rQpmKN+xGb6eZVLaTkbtrKc=; b=Udd90F4h0zCNNnbXAe+164TapFQw71wxN7u8OpVilQLDN2CAyCa7LF+znZakjhxeHJ 2JNP4csDk4coCIrwSntcXc7HRFk72zS6MDtQs17ck3OeABYzwTrOmjYSOO1FRP7r3Z71 V9FnaLbUX0Yt3I69Ps7TGVrNefJHEQXjk/7+NIvvHLL5hf2+PRpnlaIYL/Nylna7eMN7 AG4ljkSarqeOGZ+JhxAQLeV3fBotXHZqJN1izwapxqEe8bHMwfGmTW6C/I4PfGGHAWAy v22WoTAIVlvcfWu63bevXOkut85yEw/+hlcHIqhXTpB+ybvIjJSmyI4hWW9vd8g9MhKL 0vJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=gG0BeH3aPQX6+9LO5Ic0rQpmKN+xGb6eZVLaTkbtrKc=; b=ImvKp6BAfi0hSn97LgFywtif5CLxO1xGyOT5+RW7bm+kPqGt9weMTZ5B7rE8hcR1eV 3OLylDydWZloJSKrDsi7Q1m5OU/IY5O8/EJ+aAyt/v/Wv6MnJIDRmvvpy4gunu4lg92X K5ewSKNkh3TdHVCyoeREb3EFBhy6XVeuOrguYhPvFOod7Bd4EbvtoaMH8ibfpvN5UFbd EtWSIEMgPhcgX7aQ+dHI0yuYhaeGyyUt9nV2xT3SecowdKT+V6Nhx+qppcTYSYx7Y56Z FFBqJMzo5K0/6PhB250umyOkvgzFZPH/X04UWpvY6yEz95j5zOF42gP6GqESfGNrRaWt cGFA== X-Gm-Message-State: APjAAAXE7/h8wdGElwIh81r5D+hCkVKsGJnWzcySZr4o9BctkBzwGkrm BSbd9c4SzTe2+Mb2JLaGcya6LxFh X-Google-Smtp-Source: APXvYqxseWYBCRfSGJpzKVqfYOLwGQPN63KyKSEflyxw90tRLNWj/yCNvcE0oWLz6A9qW1LfWTDtfA== X-Received: by 2002:a65:610b:: with SMTP id z11mr12844675pgu.204.1557769936363; Mon, 13 May 2019 10:52:16 -0700 (PDT) Received: from ?IPv6:2620:15c:2c1:200:55c7:81e6:c7d8:94b? ([2620:15c:2c1:200:55c7:81e6:c7d8:94b]) by smtp.gmail.com with ESMTPSA id r138sm25380068pfr.2.2019.05.13.10.52.14 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Mon, 13 May 2019 10:52:15 -0700 (PDT) Subject: Re: [PATCH net] flow_dissector: disable preemption around BPF calls To: Mark Rutland , Eric Dumazet Cc: "David S . Miller" , Alexei Starovoitov , Daniel Borkmann , netdev , bpf , syzbot , Petar Penkov , Stanislav Fomichev References: <20190513163855.225489-1-edumazet@google.com> <20190513171745.GA16567@lakrids.cambridge.arm.com> <20190513172527.GB16567@lakrids.cambridge.arm.com> From: Eric Dumazet Message-ID: <49f8b98e-c717-c1c4-893d-cddccca3b887@gmail.com> Date: Mon, 13 May 2019 10:52:14 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190513172527.GB16567@lakrids.cambridge.arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 5/13/19 10:25 AM, Mark Rutland wrote: > On Mon, May 13, 2019 at 10:20:19AM -0700, 'Eric Dumazet' via syzkaller wrote: >> On Mon, May 13, 2019 at 10:17 AM Mark Rutland wrote: >>> >>> On Mon, May 13, 2019 at 09:38:55AM -0700, 'Eric Dumazet' via syzkaller wrote: >>>> Various things in eBPF really require us to disable preemption >>>> before running an eBPF program. >>> >>> Is that true for all eBPF uses? I note that we don't disable preemption >>> in the lib/test_bpf.c module, for example. >>> >>> If it's a general requirement, perhaps it's worth an assertion within >>> BPF_PROG_RUN()? >> >> The assertion is already there :) >> >> This is how syzbot triggered the report. > > Ah! :) > > I also see I'm wrong about test_bpf.c, so sorry for the noise on both > counts! No worries, thanks for reviewing !