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=-6.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 6098FC433E1 for ; Tue, 28 Jul 2020 04:11:38 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2A28820729 for ; Tue, 28 Jul 2020 04:11:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="W9/+cBJR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2A28820729 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59446 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k0Gxl-0001oy-Fq for qemu-devel@archiver.kernel.org; Tue, 28 Jul 2020 00:11:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56934) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k0Gx0-0001LN-O9 for qemu-devel@nongnu.org; Tue, 28 Jul 2020 00:10:50 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:42344 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1k0Gwy-0002Ca-Vd for qemu-devel@nongnu.org; Tue, 28 Jul 2020 00:10:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595909448; 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=hJvnt4uCU4bnE5iEMY44bT4LdlbJY8o59+uElG8tscU=; b=W9/+cBJROz35OBtCwa203KqUMOEH2GBeBp9cdrNomK2Lz6AV2FPijkzP4EOTvgpAuBj8EW r+KhKNJ7cDCwpq2HWoGbGq6WSMpwyCOg689F5j6c0ZJ+znxaQTvPkQLDGjXnzNeUXr81H8 j0Ujn4tEyh/yYBANn6udWZYXmCIOnz8= 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-81-5vZIXpgXNNuYtROFd-3kNg-1; Tue, 28 Jul 2020 00:10:44 -0400 X-MC-Unique: 5vZIXpgXNNuYtROFd-3kNg-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 7BCE5800685; Tue, 28 Jul 2020 04:10:43 +0000 (UTC) Received: from [10.72.13.242] (ovpn-13-242.pek2.redhat.com [10.72.13.242]) by smtp.corp.redhat.com (Postfix) with ESMTP id DCE0974F45; Tue, 28 Jul 2020 04:10:35 +0000 (UTC) Subject: Re: [BUG] vhost-vdpa: qemu-system-s390x crashes with second virtio-net-ccw device To: "Michael S. Tsirkin" References: <20200724165627.70c6dfd6.cohuck@redhat.com> <20200724111512-mutt-send-email-mst@kernel.org> <20200724173448.18773aec.cohuck@redhat.com> <5a0dfa0b-5a1d-e7d2-1785-8cca6ddb9db8@redhat.com> <20200727084310.7d29ec6d.cohuck@redhat.com> <676ce079-adf6-a279-c2ea-68f43146e2ac@redhat.com> <20200727104148.4ae49715.cohuck@redhat.com> <20200727074221-mutt-send-email-mst@kernel.org> <20200727091422-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <334bb885-358e-2edb-8b7e-6baec45bc0da@redhat.com> Date: Tue, 28 Jul 2020 12:10:34 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200727091422-mutt-send-email-mst@kernel.org> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=207.211.31.120; envelope-from=jasowang@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/27 23:55:28 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-s390x@nongnu.org, Cornelia Huck , qemu-devel@nongnu.org, Cindy Lu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/7/27 下午9:16, Michael S. Tsirkin wrote: > On Mon, Jul 27, 2020 at 08:44:09PM +0800, Jason Wang wrote: >> On 2020/7/27 下午7:43, Michael S. Tsirkin wrote: >>> On Mon, Jul 27, 2020 at 04:51:23PM +0800, Jason Wang wrote: >>>> On 2020/7/27 下午4:41, Cornelia Huck wrote: >>>>> On Mon, 27 Jul 2020 15:38:12 +0800 >>>>> Jason Wang wrote: >>>>> >>>>>> On 2020/7/27 下午2:43, Cornelia Huck wrote: >>>>>>> On Sat, 25 Jul 2020 08:40:07 +0800 >>>>>>> Jason Wang wrote: >>>>>>>> On 2020/7/24 下午11:34, Cornelia Huck wrote: >>>>>>>>> On Fri, 24 Jul 2020 11:17:57 -0400 >>>>>>>>> "Michael S. Tsirkin" wrote: >>>>>>>>>> On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: >>>>>>>>>>> On Fri, 24 Jul 2020 09:30:58 -0400 >>>>>>>>>>> "Michael S. Tsirkin" wrote: >>>>>>>>>>>> On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: >>>>>>>>>>>>> When I start qemu with a second virtio-net-ccw device (i.e. adding >>>>>>>>>>>>> -device virtio-net-ccw in addition to the autogenerated device), I get >>>>>>>>>>>>> a segfault. gdb points to >>>>>>>>>>>>> >>>>>>>>>>>>> #0 0x000055d6ab52681d in virtio_net_get_config (vdev=, >>>>>>>>>>>>> config=0x55d6ad9e3f80 "RT") at /home/cohuck/git/qemu/hw/net/virtio-net.c:146 >>>>>>>>>>>>> 146 if (nc->peer->info->type == NET_CLIENT_DRIVER_VHOST_VDPA) { >>>>>>>>>>>>> >>>>>>>>>>>>> (backtrace doesn't go further) >>>>>>>>>>> The core was incomplete, but running under gdb directly shows that it >>>>>>>>>>> is just a bog-standard config space access (first for that device). >>>>>>>>>>> >>>>>>>>>>> The cause of the crash is that nc->peer is not set... no idea how that >>>>>>>>>>> can happen, not that familiar with that part of QEMU. (Should the code >>>>>>>>>>> check, or is that really something that should not happen?) >>>>>>>>>>> >>>>>>>>>>> What I don't understand is why it is set correctly for the first, >>>>>>>>>>> autogenerated virtio-net-ccw device, but not for the second one, and >>>>>>>>>>> why virtio-net-pci doesn't show these problems. The only difference >>>>>>>>>>> between -ccw and -pci that comes to my mind here is that config space >>>>>>>>>>> accesses for ccw are done via an asynchronous operation, so timing >>>>>>>>>>> might be different. >>>>>>>>>> Hopefully Jason has an idea. Could you post a full command line >>>>>>>>>> please? Do you need a working guest to trigger this? Does this trigger >>>>>>>>>> on an x86 host? >>>>>>>>> Yes, it does trigger with tcg-on-x86 as well. I've been using >>>>>>>>> >>>>>>>>> s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu qemu,zpci=on >>>>>>>>> -m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 >>>>>>>>> -drive file=/path/to/image,format=qcow2,if=none,id=drive-scsi0-0-0-0 >>>>>>>>> -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 >>>>>>>>> -device virtio-net-ccw >>>>>>>>> >>>>>>>>> It seems it needs the guest actually doing something with the nics; I >>>>>>>>> cannot reproduce the crash if I use the old advent calendar moon buggy >>>>>>>>> image and just add a virtio-net-ccw device. >>>>>>>>> >>>>>>>>> (I don't think it's a problem with my local build, as I see the problem >>>>>>>>> both on my laptop and on an LPAR.) >>>>>>>> It looks to me we forget the check the existence of peer. >>>>>>>> >>>>>>>> Please try the attached patch to see if it works. >>>>>>> Thanks, that patch gets my guest up and running again. So, FWIW, >>>>>>> >>>>>>> Tested-by: Cornelia Huck >>>>>>> >>>>>>> Any idea why this did not hit with virtio-net-pci (or the autogenerated >>>>>>> virtio-net-ccw device)? >>>>>> It can be hit with virtio-net-pci as well (just start without peer). >>>>> Hm, I had not been able to reproduce the crash with a 'naked' -device >>>>> virtio-net-pci. But checking seems to be the right idea anyway. >>>> Sorry for being unclear, I meant for networking part, you just need start >>>> without peer, and you need a real guest (any Linux) that is trying to access >>>> the config space of virtio-net. >>>> >>>> Thanks >>> A pxe guest will do it, but that doesn't support ccw, right? >> >> Yes, it depends on the cli actually. >> >> >>> I'm still unclear why this triggers with ccw but not pci - >>> any idea? >> >> I don't test pxe but I can reproduce this with pci (just start a linux guest >> without a peer). >> >> Thanks >> > Might be a good addition to a unit test. Not sure what would the > test do exactly: just make sure guest runs? Looks like a lot of work > for an empty test ... maybe we can poke at the guest config with > qtest commands at least. That should work or we can simply extend the exist virtio-net qtest to do that. Thanks >