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=-4.1 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 8E38EC433F7 for ; Mon, 27 Jul 2020 08:42:40 +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 5B30E20838 for ; Mon, 27 Jul 2020 08:42:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YTU2c7nf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B30E20838 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]:33916 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jzyiV-0006d1-Jv for qemu-devel@archiver.kernel.org; Mon, 27 Jul 2020 04:42:39 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51444) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jzyhs-0006BZ-Aw for qemu-devel@nongnu.org; Mon, 27 Jul 2020 04:42:00 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:51984 helo=us-smtp-delivery-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 1jzyhq-0006Gl-CK for qemu-devel@nongnu.org; Mon, 27 Jul 2020 04:41:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595839317; 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=b+LSf5nm5L/1miKDsrnYsMGuPjFFyPqJ6bR2S/AH87s=; b=YTU2c7nfOzPpK4vXMmvq/k641KmjGtvvlT8iiTCEUpyFfTehuTNQTh1/8V6+n/yut8s2+O YzqG4dwoIVFGGW1OiIDC7y7Zj5625FMLDv+8cxXuK2THDYLnJ9V1o+la5UV08OiH1jkIjw KhPVS7fuuvaVxPQzzoxryc/6eyL6xLg= 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-473-KR1mewgOO7GN8oXbhcTNbg-1; Mon, 27 Jul 2020 04:41:55 -0400 X-MC-Unique: KR1mewgOO7GN8oXbhcTNbg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 34F99102CC41; Mon, 27 Jul 2020 08:41:52 +0000 (UTC) Received: from gondolin (ovpn-112-210.ams2.redhat.com [10.36.112.210]) by smtp.corp.redhat.com (Postfix) with ESMTP id D031A69324; Mon, 27 Jul 2020 08:41:50 +0000 (UTC) Date: Mon, 27 Jul 2020 10:41:48 +0200 From: Cornelia Huck To: Jason Wang Subject: Re: [BUG] vhost-vdpa: qemu-system-s390x crashes with second virtio-net-ccw device Message-ID: <20200727104148.4ae49715.cohuck@redhat.com> In-Reply-To: <676ce079-adf6-a279-c2ea-68f43146e2ac@redhat.com> References: <20200724152718.4e1cbc9e.cohuck@redhat.com> <20200724092906-mutt-send-email-mst@kernel.org> <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> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=207.211.31.81; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/27 03:37:14 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=ham 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, qemu-devel@nongnu.org, Cindy Lu , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, 27 Jul 2020 15:38:12 +0800 Jason Wang wrote: > On 2020/7/27 =E4=B8=8B=E5=8D=882:43, Cornelia Huck wrote: > > On Sat, 25 Jul 2020 08:40:07 +0800 > > Jason Wang wrote: > > =20 > >> On 2020/7/24 =E4=B8=8B=E5=8D=8811:34, Cornelia Huck wrote: =20 > >>> On Fri, 24 Jul 2020 11:17:57 -0400 > >>> "Michael S. Tsirkin" wrote: > >>> =20 > >>>> On Fri, Jul 24, 2020 at 04:56:27PM +0200, Cornelia Huck wrote: =20 > >>>>> On Fri, 24 Jul 2020 09:30:58 -0400 > >>>>> "Michael S. Tsirkin" wrote: > >>>>> =20 > >>>>>> On Fri, Jul 24, 2020 at 03:27:18PM +0200, Cornelia Huck wrote: =20 > >>>>>>> When I start qemu with a second virtio-net-ccw device (i.e. addin= g > >>>>>>> -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=3D, > >>>>>>> config=3D0x55d6ad9e3f80 "RT") at /home/cohuck/git/qemu/hw/n= et/virtio-net.c:146 > >>>>>>> 146=09 if (nc->peer->info->type =3D=3D NET_CLIENT_DRIVER_VHOST= _VDPA) { > >>>>>>> > >>>>>>> (backtrace doesn't go further) =20 > >>>>> 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 t= hat > >>>>> can happen, not that familiar with that part of QEMU. (Should the c= ode > >>>>> 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, an= d > >>>>> 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 spa= ce > >>>>> accesses for ccw are done via an asynchronous operation, so timing > >>>>> might be different. =20 > >>>> Hopefully Jason has an idea. Could you post a full command line > >>>> please? Do you need a working guest to trigger this? Does this trigg= er > >>>> on an x86 host? =20 > >>> Yes, it does trigger with tcg-on-x86 as well. I've been using > >>> > >>> s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=3Dtcg -cpu q= emu,zpci=3Don > >>> -m 1024 -nographic -device virtio-scsi-ccw,id=3Dscsi0,devno=3Dfe.0.00= 01 > >>> -drive file=3D/path/to/image,format=3Dqcow2,if=3Dnone,id=3Ddrive-scsi= 0-0-0-0 > >>> -device scsi-hd,bus=3Dscsi0.0,channel=3D0,scsi-id=3D0,lun=3D0,drive= =3Ddrive-scsi0-0-0-0,id=3Dscsi0-0-0-0,bootindex=3D1 > >>> -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 bugg= y > >>> 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 probl= em > >>> both on my laptop and on an LPAR.) =20 > >> > >> It looks to me we forget the check the existence of peer. > >> > >> Please try the attached patch to see if it works. =20 > > 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)? =20 >=20 >=20 > 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. >=20 > For autogenerated virtio-net-cww, I think the reason is that it has=20 > already had a peer set. Ok, that might well be.