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=-5.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,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 E7E3AC432C0 for ; Mon, 2 Dec 2019 17:11:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B99A120833 for ; Mon, 2 Dec 2019 17:11:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="E9g04maQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727818AbfLBRLY (ORCPT ); Mon, 2 Dec 2019 12:11:24 -0500 Received: from mail-lj1-f196.google.com ([209.85.208.196]:45876 "EHLO mail-lj1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727618AbfLBRLX (ORCPT ); Mon, 2 Dec 2019 12:11:23 -0500 Received: by mail-lj1-f196.google.com with SMTP id d20so254717ljc.12; Mon, 02 Dec 2019 09:11:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=lpXTTJYa93HPPwo+Z8D2FxtkYP9FJXZjmmqaDUf8VaQ=; b=E9g04maQVIBCqRxru4XzIIVPCWLg64d60N7C1BB9CogSSuFO2kAfZikv7f7ZZhlreD flUIUUTBprsfqCUdRLaFKdMmE7ZEEg/I49MNQznUnzw6qyyERDXxuq5IsuwzybPZIYy6 B80djTP13Csl7cYKezxlFGhIsF28UabrGMMoHpliQB+A++RDycsneZO9RGH2k5Ofc1w9 kT6uSocZK+b7eez1M7j2QeVVvC/EcnbKL3nLhpTAvDv3+ptL9MDm1lZNcYigsDnelktU 4k4F6N6VvOyb+rn/iqhjfOXG88RRLUjMP8eoT+69G7eL/tMCFTPr4Nj/h6YXSOGJGBgW SP1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lpXTTJYa93HPPwo+Z8D2FxtkYP9FJXZjmmqaDUf8VaQ=; b=EFGVdVMuYBAqDoh3SO12TxANHnVxu4caPRtMMgLNm+a0akmA3kKCkmgncKkvErrXxl rK6kjsX25gvIPJKlsQA2/6Y59SJpNNSrWahzpncy7G3+bUbA119A1/3be0B/sPzTtDzS RGoNNYUA4iZXVRvfo8UbBqLRgh8SU/ZVG2/UXf7GYlNWkRvYEKEGJ+qLlBKg4SLlfmUp 1OTippBabvkFIzi81+zQJZUhUOGRG9IZxqV1H8s8X/jG2Y3uYush/VrRBNHcwbwBELZB FeRy12HXpgXOGzNFyaMRzrE7lciLNcEu510qKM0VrvcAO91lD92HWMRT4juojlov5dhr lcwA== X-Gm-Message-State: APjAAAV0d4Z2RAEYkeOzhYrYL06IfHHFcN4Xp9EhLG7z5cpwD51gjgnA 0RUhfCu1YTuoEr8o81yooFie+/qo+hfNNLhtphs= X-Google-Smtp-Source: APXvYqwvX2YSTp98I8S0ycyL/X5UhxVECvuh6tjh70qyuJdgly0QGQA05gHw6kuFWXvF6MbhiYfWSc86DjT78sEyW9E= X-Received: by 2002:a2e:58c:: with SMTP id 134mr34674239ljf.12.1575306680817; Mon, 02 Dec 2019 09:11:20 -0800 (PST) MIME-Version: 1.0 References: <20191129164842.qimcmjlz5xq7uupw@linutronix.de> <20191202162651.7jkyj52sny3yownr@linutronix.de> In-Reply-To: <20191202162651.7jkyj52sny3yownr@linutronix.de> From: Paul Thomas Date: Mon, 2 Dec 2019 12:11:08 -0500 Message-ID: Subject: Re: xdpsock poll with 5.2.21rt kernel To: Sebastian Andrzej Siewior Cc: Alexei Starovoitov , Daniel Borkmann , David Miller , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend , netdev@vger.kernel.org, xdp-newbies@vger.kernel.org, bpf@vger.kernel.org, linux-rt-users Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > > > > Well, it does complain (report below), but I'm not sure it's related. > > The other thing I tried was the AF_XDP example here: > > https://github.com/xdp-project/xdp-tutorial/tree/master/advanced03-AF_XDP > > > > With this example poll() always seems to block correctly, so I think > > maybe there is something wrong with the xdpsock_user.c example or how > > I'm using it. > > > > [ 259.591480] BUG: assuming atomic context at net/core/ptp_classifier.c:106 > > [ 259.591488] in_atomic(): 0, irqs_disabled(): 0, pid: 953, name: irq/22-eth%d > > [ 259.591494] CPU: 0 PID: 953 Comm: irq/22-eth%d Tainted: G WC > > 5. > > > > 2.21-rt13-00016-g93898e751d0e #90 > > [ 259.591499] Hardware name: Enclustra XU5 SOM (DT) > > [ 259.591501] Call trace: > > [ 259.591503] dump_backtrace (/arch/arm64/kernel/traps.c:94) > > [ 259.591514] show_stack (/arch/arm64/kernel/traps.c:151) > > [ 259.591520] dump_stack (/lib/dump_stack.c:115) > > [ 259.591526] __cant_sleep (/kernel/sched/core.c:6386) > > [ 259.591531] ptp_classify_raw (/./include/linux/compiler.h:194 > > Is this the only splat? Nothing more? I would expect something at boot > time, too. I should have expanded more. This seems to happen every second starting at boot in ptp_classifier.c regardless of if I'm doing anything with BPF. > > So this part expects disabled preemption. Other invocations disable > preemption. The whole BPF part is currently not working on -RT. OK, so I should expect more issues as we play with AF_XDP? An application based on the other example [1] is at least running. Preempt-rt + AF_XDP seems like an awesome combination, so I hopefully any BPF issues can be resolved. thanks, Paul [1] https://github.com/xdp-project/xdp-tutorial/tree/master/advanced03-AF_XDP