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=-5.8 required=3.0 tests=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 CE5E1C43215 for ; Mon, 2 Dec 2019 16:27:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A44E320748 for ; Mon, 2 Dec 2019 16:27:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727637AbfLBQ1F (ORCPT ); Mon, 2 Dec 2019 11:27:05 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:52828 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727431AbfLBQ1E (ORCPT ); Mon, 2 Dec 2019 11:27:04 -0500 Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1iboXD-0002vI-M1; Mon, 02 Dec 2019 17:26:51 +0100 Date: Mon, 2 Dec 2019 17:26:51 +0100 From: Sebastian Andrzej Siewior To: Paul Thomas 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 Subject: Re: xdpsock poll with 5.2.21rt kernel Message-ID: <20191202162651.7jkyj52sny3yownr@linutronix.de> References: <20191129164842.qimcmjlz5xq7uupw@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2019-12-02 10:36:54 [-0500], Paul Thomas wrote: > On Fri, Nov 29, 2019 at 11:48 AM Sebastian Andrzej Siewior > wrote: > > > > On 2019-11-12 17:42:42 [-0500], Paul Thomas wrote: > > > Any thoughts would be appreciated. > > > > Could please enable CONFIG_DEBUG_ATOMIC_SLEEP and check if the kernel > > complains? > > Hi Sebastian, > > 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. So this part expects disabled preemption. Other invocations disable preemption. The whole BPF part is currently not working on -RT. Sebastian