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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 7ADB4C433DB for ; Mon, 21 Dec 2020 18:49:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3230922AAB for ; Mon, 21 Dec 2020 18:49:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727234AbgLUSty (ORCPT ); Mon, 21 Dec 2020 13:49:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:52110 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727220AbgLUSty (ORCPT ); Mon, 21 Dec 2020 13:49:54 -0500 Date: Mon, 21 Dec 2020 10:47:57 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1608576480; bh=gTGZfpII5i36fRI++AgefpXMI0LpZgdmm0CChJOkdbQ=; h=From:To:Cc:Subject:In-Reply-To:References:From; b=P+yPfGWu6pHp9hgsdBKJvEgrOmFXkVuDTqcyYIeJro2C3obApB7sshTq385G5/8L+ q8cAsbq1neQOFPMAJx9G4io82WOHiqf1JjqyNc993uslBpjOYOOGnDR9v7xB7BLwAJ LjC4Z9Cx+UH5nBqC04DGmG+LUh8HgmW3MKyPYeUa6A837yh4UmO8wriye/nlZTt3Gy CaI78p/k+f1Sjpo54/+MgtDAqwWs8FMCNf5LlqoKwvMFF8OwgBMkiLTBbQiMZvTfgs p+czOb8gWudNwACRZHjhR3MwW0SYiNbK35U1wvgQ6WBB6490VQulzn8bHQ8F21dbuU GyCiZtFhwts1Q== From: Jakub Kicinski To: Russell King - ARM Linux admin , stable@vger.kernel.org Cc: Marcin Wojtas , Sasha Levin , Antoine Tenart , Alexandre Belloni , "David S. Miller" , netdev , Gabor Samu , Jon Nettleton , Andrew Elwell , Greg Kroah-Hartman Subject: Re: [PATCH net-next 2/4] net: mvpp2: add mvpp2_phylink_to_port() helper Message-ID: <20201221104757.2cd8d68c@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20201221183032.GA1551@shell.armlinux.org.uk> References: <20201102180326.GA2416734@kroah.com> <20201208133532.GH643756@sasha-vm> <20201221102539.6bdb9f5c@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20201221183032.GA1551@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 21 Dec 2020 18:30:32 +0000 Russell King - ARM Linux admin wrote: > On Mon, Dec 21, 2020 at 10:25:39AM -0800, Jakub Kicinski wrote: > > We need to work with stable maintainers on this, let's see.. > > > > Greg asked for a clear description of what happens, from your > > previous response it sounds like a null-deref in mvpp2_mac_config(). > > Is the netdev -> config -> netdev linking not ready by the time > > mvpp2_mac_config() is called? > > We are going round in circles, so nothing is going to happen. > > I stated in detail in one of my emails on the 10th December why the > problem occurs. So, Greg has the description already. There is no > need to repeat it. > > Can we please move forward with this? Well, the fact it wasn't quoted in Marcin's reply and that I didn't spot it when scanning the 30 email thread should be a clear enough indication whether pinging threads is a good strategy.. A clear, fresh backport request would had been much more successful and easier for Greg to process. If you still don't see a reply in 2 weeks, please just do that. In case Greg is in fact reading this: Greg, can we backport: 6c2b49eb9671 ("net: mvpp2: add mvpp2_phylink_to_port() helper") to 5.4? Quoting Russell: The problem is that mvpp2_acpi_start() passes an un-initialised (zeroed) port->phylink_config, as phylink is not used in ACPI setups. Crash occurs because port->phylink_config.dev (which is a NULL pointer in this instance) is passed to to_net_dev(): #define to_net_dev(d) container_of(d, struct net_device, dev) Which then means netdev_priv(dev) attempts to dereference a not-quite NULL pointer, leading to an oops. Folks here are willing to provide a more cut down fix if necessary. Thanks!