From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:41621) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hERfi-00084a-17 for qemu-devel@nongnu.org; Thu, 11 Apr 2019 00:50:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hERfh-0004yP-0j for qemu-devel@nongnu.org; Thu, 11 Apr 2019 00:50:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44240) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hERfg-0004x9-JX for qemu-devel@nongnu.org; Thu, 11 Apr 2019 00:50:44 -0400 References: <20190407092314.11066-1-thuth@redhat.com> <20190408134517.GA9047@richard> <14147807-8723-adac-dffb-31b7bbd0fc3b@redhat.com> <20190408212911.jiqdva62ddebndut@master> <20190411015619.GA9198@richard> From: Thomas Huth Message-ID: <8c0c99e1-3f9c-f852-aa0d-7a4a31856392@redhat.com> Date: Thu, 11 Apr 2019 06:50:38 +0200 MIME-Version: 1.0 In-Reply-To: <20190411015619.GA9198@richard> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-4.0] hw/i386/pc: Fix crash when hot-plugging nvdimm on older machine types List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wei Yang , Wei Yang Cc: qemu-devel@nongnu.org, Paolo Bonzini , Xiao Guangrong , Eduardo Habkost , "Michael S. Tsirkin" Hi, On 11/04/2019 03.56, Wei Yang wrote: > On Mon, Apr 08, 2019 at 09:29:11PM +0000, Wei Yang wrote: >>>> >>>> Thomas, >>>> >>>> Thanks for pointing this out, while I have some different idea on how to fix >>>> this. >>>> >>>> The reason of the core dump is errp already been set in >>>> hotplug_handler_pre_plug(), and this function check acpi hotplug capability. >>>> The order of this check is correct, while we should return when errp is set >>>> in hotplug_handler_pre_plug(). >>>> >>>> I got a fix like this, which I have tested and looks good to me. >>>> >>>> >>>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c >>>> index 6077d27361..b11f3b15c1 100644 >>>> --- a/hw/i386/pc.c >>>> +++ b/hw/i386/pc.c >>>> @@ -2091,6 +2091,9 @@ static void pc_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, >>>> } >>>> >>>> hotplug_handler_pre_plug(pcms->acpi_dev, dev, errp); >>>> + if (*errp) { >>>> + return; >>>> + } >>> >>> Not sure, but I think you can not rely on the fact that the caller set >>> *errp = NULL already... that's why it is more common to use a local_err >>> variable and error_propagate() for such cases (which is what I did in my >>> patch). >>> >> >> Ok, that's fine for me. >> >>> Also, why don't you want the "nvdimm is not enabled: missing 'nvdimm' in >>> '-M'" check to be done first? >>> >> >> Because this function pc_memory_pre_plug() will be called not only when >> nvdimm is hot-plugged but also dimm is hot-plugged. And >> hotplug_handler_pre_plug() here is to check the acpi(if it has) hot-plug >> capability. >> >> So the check in pc_memory_pre_plug() is from generic to specific: >> 1. Do we have capability to hot-plug? >> 2. If the device is nvdimm, do we enabled nvdimm? >> > > Thomas > > Do you think this is a reasonable explanation? Fine for me, I don't mind either way as long as the crash is fixed. Feel free to send a patch that restores the desired order. Thomas 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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 71CA0C10F13 for ; Thu, 11 Apr 2019 04:51:38 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2BE5E2133D for ; Thu, 11 Apr 2019 04:51:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2BE5E2133D 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 ([127.0.0.1]:41813 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hERgX-0008Q4-2D for qemu-devel@archiver.kernel.org; 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Thu, 11 Apr 2019 04:50:39 +0000 (UTC) To: Wei Yang , Wei Yang References: <20190407092314.11066-1-thuth@redhat.com> <20190408134517.GA9047@richard> <14147807-8723-adac-dffb-31b7bbd0fc3b@redhat.com> <20190408212911.jiqdva62ddebndut@master> <20190411015619.GA9198@richard> From: Thomas Huth Openpgp: preference=signencrypt Autocrypt: addr=thuth@redhat.com; keydata= xsFNBFH7eUwBEACzyOXKU+5Pcs6wNpKzrlJwzRl3VGZt95VCdb+FgoU9g11m7FWcOafrVRwU yYkTm9+7zBUc0sW5AuPGR/dp3pSLX/yFWsA/UB4nJsHqgDvDU7BImSeiTrnpMOTXb7Arw2a2 4CflIyFqjCpfDM4MuTmzTjXq4Uov1giGE9X6viNo1pxyEpd7PanlKNnf4PqEQp06X4IgUacW tSGj6Gcns1bCuHV8OPWLkf4hkRnu8hdL6i60Yxz4E6TqlrpxsfYwLXgEeswPHOA6Mn4Cso9O 0lewVYfFfsmokfAVMKWzOl1Sr0KGI5T9CpmRfAiSHpthhHWnECcJFwl72NTi6kUcUzG4se81 O6n9d/kTj7pzTmBdfwuOZ0YUSqcqs0W+l1NcASSYZQaDoD3/SLk+nqVeCBB4OnYOGhgmIHNW 0CwMRO/GK+20alxzk//V9GmIM2ACElbfF8+Uug3pqiHkVnKqM7W9/S1NH2qmxB6zMiJUHlTH gnVeZX0dgH27mzstcF786uPcdEqS0KJuxh2kk5IvUSL3Qn3ZgmgdxBMyCPciD/1cb7/Ahazr 3ThHQXSHXkH/aDXdfLsKVuwDzHLVSkdSnZdt5HHh75/NFHxwaTlydgfHmFFwodK8y/TjyiGZ zg2Kje38xnz8zKn9iesFBCcONXS7txENTzX0z80WKBhK+XSFJwARAQABzRxUaG9tYXMgSHV0 aCA8dGguaHV0aEBnbXguZGU+wsF7BBMBAgAlAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIX gAUCUfuWKwIZAQAKCRAu2dd0/nAttbe/EACb9hafyOb2FmhUqeAiBORSsUifFacQ7laVjcgR I4um8CSHvxijYftpkM2EdAtmXIKgbNDpQoXcWLXB9lu9mLgTO4DVT00TRR65ikn3FCWcyT74 ENTOzRKyKLsDCjhXKPblTPIQbYAUCOWElcyAPm0ERd62fA/rKNxgIiNo/l4UODOMoOJm2/Ox ZoTckW68Eqv7k9L7m7j+Hn3hoDTjAmcCBJt+j7pOhzWvCbqoNOIH8C8qvPaNlrba+R/K6jkO 6jZkTbYQpGIofEQJ/TNn38IsNGpI1ALTHWFtoMxp3j2Imz0REO6dRE2fHRN8sVlHgkoeGhmY NbDsDE1jFQOEObFnu0euk//7BXU7tGOHckVAZ8T1smiRPHfQU7UEH2a/grndxJ+PNeM5w7n2 l+FN3cf2KgPotCK2s9MjSdZA7C5e3rFYO8lqiqTJKvc62vqp3e7B0Kjyy5/QtzSOejBij2QL xkKSFNtxIz4MtuxN8e3IDQNxsKry3nF7R4MDvouXlMo6wP9KuyNWb+vFJt9GtbgfDMIFVamp ZfhEWzWRJH4VgksENA4K/BzjEHCcbTUb1TFsiB1VRnBPJ0SqlvifnfKk6HcpkDk6Pg8Q5FOJ gbNHrdgXsm+m/9GF2zUUr+rOlhVbK23TUqKqPfwnD7uxjpakVcJnsVCFqJpZi1F/ga9IN87B TQRR+3lMARAAtp831HniPHb9AuKq3wj83ujZK8lH5RLrfVsB4X1wi47bwo56BqhXpR/zxPTR eOFT0gnbw9UkphVc7uk/alnXMDEmgvnuxv89PwIQX6k3qLABeV7ykJQG/WT5HQ6+2DdGtVw3 2vjYAPiWQeETsgWRRQMDR0/hwp8s8tL/UodwYCScH6Vxx9pdy353L1fK4Bb9G73a+9FPjp9l x+WwKTsltVqSBuSjyZQ3c3EE8qbTidXZxB38JwARH8yN3TX+t65cbBqLl/zRUUUTapHQpUEd yoAsHIml32e4q+3xdLtTdlLi7FgPBItSazcqZPjEcYW73UAuLcmQmfJlQ5PkDiuqcitn+KzH /1pqsTU7QFZjbmSMJyXY0TDErOFuMOjf20b6arcpEqse1V3IKrb+nqqA2azboRm3pEANLAJw iVTwK3qwGRgK5ut6N/Znv20VEHkFUsRAZoOusrIRfR5HFDxlXguAdEz8M/hxXFYYXqOoaCYy 6pJxTjy0Y/tIfmS/g9Bnp8qg9wsrsnk0+XRnDVPak++G3Uq9tJPwpJbyO0vcqEI3vAXkAB7X VXLzvFwi66RrsPUoDkuzj+aCNumtOePDOCpXQGPpKl+l1aYRMN/+lNSk3+1sVuc2C07WnYyE gV/cbEVklPmKrNwu6DeUyD0qI/bVzKMWZAiB1r56hsGeyYcAEQEAAcLBXwQYAQIACQUCUft5 TAIbDAAKCRAu2dd0/nAttYTwEACLAS/THRqXRKb17PQmKwZHerUvZm2klo+lwQ3wNQBHUJAT p2R9ULexyXrJPqjUpy7+voz+FcKiuQBTKyieiIxO46oMxsbXGZ70o3gxjxdYdgimUD6U8PPd JH8tfAL4BR5FZNjspcnscN2jgbF4OrpDeOLyBaj6HPmElNPtECHWCaf1xbIFsZxSDGMA6cUh 0uX3Q8VI7JN1AR2cfiIRY7NrIlWYucJxyKjO3ivWm69nCtsHiJ0wcF8KlVo7F2eLaufo0K8A ynL8SHMF3VEyxsXOP2f1UR9T2Ur30MXcTBpjUxml1TX3RWY5uH89Js/jlIugBwuAmacJ7JYh lTg6sF/GNc4nPb4kk2yktNWTade+TzsllYlJPaorD2Qe8qX0iFUhFC6y9+O6mP4ZvWoYapp9 ezYNuebMgEr93ob1+4sFg3812wNP01WqsGtWCJHnPv/JoonFdMzD/bIkXGEJMk6ks2kxQQZq g6Ik/s/vxOfao/xCn8nHt7GwvVy41795hzK6tbSl+BuyCRp0vfPRP34OnK7+jR2nvQpJu/pU rCELuGwT9hsYkUPjVd4lfylN3mzEc6iAv/wwjsc0DRTSQCpXT3v2ymTAsRKrVaEZLibTXaf+ WslxWek3xNYRiqwwWAJuL652eAlxUgQ5ZS+fXBRTiQpJ+F26I/2lccScRd9G5w== Organization: Red Hat Message-ID: <8c0c99e1-3f9c-f852-aa0d-7a4a31856392@redhat.com> Date: Thu, 11 Apr 2019 06:50:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190411015619.GA9198@richard> Content-Type: text/plain; charset="UTF-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 11 Apr 2019 04:50:43 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH for-4.0] hw/i386/pc: Fix crash when hot-plugging nvdimm on older machine types X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , "Michael S. Tsirkin" , qemu-devel@nongnu.org, Eduardo Habkost , Xiao Guangrong Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190411045038.MjrdBxbjL5GxbVtpGrjNXsZz6pFi4b6coly8TkZwMWY@z> Hi, On 11/04/2019 03.56, Wei Yang wrote: > On Mon, Apr 08, 2019 at 09:29:11PM +0000, Wei Yang wrote: >>>> >>>> Thomas, >>>> >>>> Thanks for pointing this out, while I have some different idea on how to fix >>>> this. >>>> >>>> The reason of the core dump is errp already been set in >>>> hotplug_handler_pre_plug(), and this function check acpi hotplug capability. >>>> The order of this check is correct, while we should return when errp is set >>>> in hotplug_handler_pre_plug(). >>>> >>>> I got a fix like this, which I have tested and looks good to me. >>>> >>>> >>>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c >>>> index 6077d27361..b11f3b15c1 100644 >>>> --- a/hw/i386/pc.c >>>> +++ b/hw/i386/pc.c >>>> @@ -2091,6 +2091,9 @@ static void pc_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, >>>> } >>>> >>>> hotplug_handler_pre_plug(pcms->acpi_dev, dev, errp); >>>> + if (*errp) { >>>> + return; >>>> + } >>> >>> Not sure, but I think you can not rely on the fact that the caller set >>> *errp = NULL already... that's why it is more common to use a local_err >>> variable and error_propagate() for such cases (which is what I did in my >>> patch). >>> >> >> Ok, that's fine for me. >> >>> Also, why don't you want the "nvdimm is not enabled: missing 'nvdimm' in >>> '-M'" check to be done first? >>> >> >> Because this function pc_memory_pre_plug() will be called not only when >> nvdimm is hot-plugged but also dimm is hot-plugged. And >> hotplug_handler_pre_plug() here is to check the acpi(if it has) hot-plug >> capability. >> >> So the check in pc_memory_pre_plug() is from generic to specific: >> 1. Do we have capability to hot-plug? >> 2. If the device is nvdimm, do we enabled nvdimm? >> > > Thomas > > Do you think this is a reasonable explanation? Fine for me, I don't mind either way as long as the crash is fixed. Feel free to send a patch that restores the desired order. Thomas