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=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 4885FC433B4 for ; Sat, 8 May 2021 01:00:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F124161421 for ; Sat, 8 May 2021 01:00:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230152AbhEHBBw (ORCPT ); Fri, 7 May 2021 21:01:52 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:21534 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229524AbhEHBBv (ORCPT ); Fri, 7 May 2021 21:01:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1620435651; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ME5pagLhdcdp2EfQiF12b7sWVV6mylj3kTUPAbdQpRY=; b=d0I+T8fn0i3Eytal/FRplCbsRVbPX7KFWgTiNdT3VBx0WlxNV7+WZhczPYRf7cbgzZ6XLn fyIUMalFEmHpzhMUVstcUIb8NJm9Qxjn2awPuR3IO8qv9xYZTZk0OKsdMN+8q6bwyTjjLb CA2VeX4YS61ateDygZFmdfLmqJJ5gKY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-480-vkp5euYoOgOBwtLoU5_EiQ-1; Fri, 07 May 2021 21:00:49 -0400 X-MC-Unique: vkp5euYoOgOBwtLoU5_EiQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5F27C80059E; Sat, 8 May 2021 01:00:48 +0000 (UTC) Received: from maya.cloud.tilaa.com (unknown [10.36.110.6]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3601436D5; Sat, 8 May 2021 01:00:48 +0000 (UTC) Date: Sat, 8 May 2021 03:00:46 +0200 From: Stefano Brivio To: Arturo Borrero Gonzalez Cc: "netfilter-devel@vger.kernel.org" Subject: Re: nft_pipapo_avx2_lookup backtrace in linux 5.10 Message-ID: <20210508030046.4ae872f6@redhat.com> In-Reply-To: References: <8ff71ad7-7171-c8c7-f31b-d4bd7577cc18@netfilter.org> <20210507123636.030e98ef@elisabeth> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Fri, 7 May 2021 13:12:43 +0200 Arturo Borrero Gonzalez wrote: > However, the nft ruleset is quite simple. It should be possible for you to grab > a similar arch CPU, introduce the ruleset and generate some traffic to trigger > the lookup(), no? Unfortunately, this has little to do with the ruleset, it's rather about the fact that a kthread using the FPU gets interrupted by net_rx_action() which ends up in a call to nft_pipapo_avx2_lookup(), which also uses the FPU. The amount of luck I'd need to hit this with some ext4 worklaod together with packet classification discourages me from even trying. ;) But luckily my mistake here looks simple enough to fix. -- Stefano