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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 50A41C352AA for ; Wed, 2 Oct 2019 14:15:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 17E7721A4C for ; Wed, 2 Oct 2019 14:15:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="O8nRxt/M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728086AbfJBOPK (ORCPT ); Wed, 2 Oct 2019 10:15:10 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:54624 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726200AbfJBOPJ (ORCPT ); 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Wed, 02 Oct 2019 14:15:01 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x92E4BJ3046750; Wed, 2 Oct 2019 14:15:00 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3030.oracle.com with ESMTP id 2vcg61cq8b-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 02 Oct 2019 14:15:00 +0000 Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x92EEwXZ029339; Wed, 2 Oct 2019 14:14:59 GMT Received: from bostrovs-us.us.oracle.com (/10.152.32.65) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 02 Oct 2019 07:14:58 -0700 Subject: Re: [Xen-devel] [PATCH] x86/xen: Return from panic notifier To: Jan Beulich Cc: james@dingwall.me.uk, xen-devel@lists.xenproject.org, Juergen Gross , linux-kernel@vger.kernel.org References: <20191001151633.1659-1-boris.ostrovsky@oracle.com> <9b3f955c-ad76-601f-2b58-fa9dc4608c72@suse.com> <924f41b2-7779-9c56-9b71-56523756ecdc@oracle.com> <5650904d-b616-5ee7-216a-a0ac28d7426d@suse.com> From: Boris Ostrovsky Openpgp: preference=signencrypt Autocrypt: addr=boris.ostrovsky@oracle.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <5650904d-b616-5ee7-216a-a0ac28d7426d@suse.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9397 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=959 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910020136 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9397 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910020136 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/2/19 9:42 AM, Jan Beulich wrote: > > I can only guess that the thinking probably was that e.g. external > dumping (by the tool stack) would be more reliable (including but > not limited to this meaning less change of state from when the > original crash reason was detected) than having the domain dump > itself. We could register an external dumper (controlled by a boot option perhaps, off by default) that will call directly into hypervisor with SHUTDOWN_crash. That will guarantee that we will complete the notifier chain without relying on priorities. (Of course this still won't address a possible new feature in panic() that might be called post-dumping) If you think it's worth doing this can be easily added. -boris > True. I guess more control over the behavior needs to be given to > the admin, as either approach has its up- and downsides >