From mboxrd@z Thu Jan 1 00:00:00 1970 From: Antoine Tenart Subject: Re: [BUG] MVPP2 driver exploding in presence of a tap interface Date: Tue, 30 Oct 2018 11:50:15 +0100 Message-ID: <20181030105015.GB3407@kwain> References: <6355174d-4ab6-595d-17db-311bce607aef@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Cc: Thomas Petazzoni , Maxime Chevallier , Antoine Tenart , Marcin Wojtas , "linux-arm-kernel@lists.infradead.org" , "netdev@vger.kernel.org" To: Marc Zyngier Return-path: Received: from mail.bootlin.com ([62.4.15.54]:54358 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726225AbeJ3TnZ (ORCPT ); Tue, 30 Oct 2018 15:43:25 -0400 Content-Disposition: inline In-Reply-To: <6355174d-4ab6-595d-17db-311bce607aef@arm.com> Sender: netdev-owner@vger.kernel.org List-ID: Marc, On Mon, Oct 29, 2018 at 03:05:53PM +0000, Marc Zyngier wrote: > > This is a follow-up on the conversation Thomas and I had last week at > ELC, with me ranting at the sorry state of the MVPP2 driver. > Triggering this is dead simple: > - Add a macvtap to one of the MVPP2 interfaces > - Bring it online > - Watch the kernel exploding and memory being corrupted > > You don't even need anything listening on the tap interface, just its > simple existence triggers it. I use a similar setup on a large variety > of machines, and this box is the only one that catches fire. Removing > the macvtap interface makes it (more) reliable. > > Given that I cannot reproduce this issue on any other ARM (32 or 64bit) > platform, including other Marvell stuff, I can only conclude that the > MVPP2 driver is responsible for this. > > Example crash and .config below (4.19 vanilla, as linux/master dies in > new and wonderful ways on this box). I'm looking forward to testing any > idea you may have. I used a 4.19 vanilla kernel, with both your configuration and mine, on 2 different Macchiatobins, but was unable to trigger the issue: # ip link set eth0 up # ip link add link eth0 name macvtap0 type macvtap # ip link set macvtap0 up I can even configure the eth0/macvtap0 interfaces, and use them generating or receiving tcp/udp/icmp traffic. (I also made other tests using macvtap and tap interfaces). How much memory do you have on the board? What version of ATF are you using? Version of U-Boot? Antoine -- Antoine Ténart, Bootlin Embedded Linux and Kernel engineering https://bootlin.com