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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 23179C41535 for ; Tue, 19 Dec 2023 12:09:49 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rFYuG-0003MM-OW; Tue, 19 Dec 2023 07:09:04 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rFYuE-0003Km-Ky for qemu-devel@nongnu.org; Tue, 19 Dec 2023 07:09:02 -0500 Received: from mail-pf1-x433.google.com ([2607:f8b0:4864:20::433]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1rFYuB-0006Nc-O2 for qemu-devel@nongnu.org; Tue, 19 Dec 2023 07:09:02 -0500 Received: by mail-pf1-x433.google.com with SMTP id d2e1a72fcca58-6ce934e9d51so2267844b3a.1 for ; Tue, 19 Dec 2023 04:08:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=daynix-com.20230601.gappssmtp.com; s=20230601; t=1702987738; x=1703592538; darn=nongnu.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=wxsjwpH1JV73RfMCcGzcn4dvmAF+Npb9UCHvc+CDUG0=; b=N7Ld/Q/NpR6qe/8eukYMjBcAtdE+CbHEpRUVCm7CImzJEmGh0bHedsnv27Zp6+p2fe 7YSIXsVLijJNHCitxcTNnJpMOyf+qCAlJv9fmfKleWsO3ThBerF7dd0p//d6Za43/31o Yn/EgJs0wpSEHiRpQPtc6YWClYAn3hwWskfrUuOta9V2cgppJmpN+T5Ti6U0vMPRjtZC WvTlVRW1QJ5FSeowYZauUCvPqKGqTiSO20UeaKhgVm3J4ce3W0zzxy1lkpFL5fypgAIz cuKJjvaHCnnz3SwftCyT+0z0ExZYtoKbcQadbgfV5hXXkwEOEVNDwG77vR/+3ZoJ71N3 9aXQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702987738; x=1703592538; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wxsjwpH1JV73RfMCcGzcn4dvmAF+Npb9UCHvc+CDUG0=; b=FSJ5oOYfuZY2MfUTdb3DYoQrAJ7+HT0jKEdatIo2eQK0oq5FS9tbliSR9CuwK24M1Z mm3xqDl1dSZLonjpNYOC4WxHZaDXwlOqr9KSG+V+gw3V6lai8TCGelrK9pWYkwqpT4ah k9d+bxO6kVUypJTmkpujGZV++uGUAWh/Cz4XUfzabk9HUpxKuA6WrFk5TwXRDuttyH/Z qPfCYQG49sLZhz0oulbOLqi+d/QLu9tKYYIbxjTxthd+IMP39DuJP9O77Q5UnMn0KdbQ +p+/qcmTFK5eyyyez2tqMCcBT8YqclK2O9HYOTuExcaGjSNjXX2fwXMVL5+QbyyM4i+Z z7Sg== X-Gm-Message-State: AOJu0YztMhhhfwQIdxzCN+vDPnSbIk8C0xcyEQBJZoWYgLxnc7e1xpHP jex0ppGhN/HHLaTM1HSlzRLdBw== X-Google-Smtp-Source: AGHT+IHoCTvbUVyr9d1n0NlfQG5j2blxhwuI6rq61fn5Aa2lno0l96XIwakmfMtw6588e3BOet7+Pg== X-Received: by 2002:a05:6a20:a11f:b0:190:4c11:28a3 with SMTP id q31-20020a056a20a11f00b001904c1128a3mr10664334pzk.6.1702987738360; Tue, 19 Dec 2023 04:08:58 -0800 (PST) Received: from [157.82.205.15] ([157.82.205.15]) by smtp.gmail.com with ESMTPSA id g22-20020a62e316000000b006d273997cd5sm6249019pfh.91.2023.12.19.04.08.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 19 Dec 2023 04:08:58 -0800 (PST) Message-ID: Date: Tue, 19 Dec 2023 21:08:45 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] qdev: Report an error for machine without HotplugHandler To: Markus Armbruster Cc: Paolo Bonzini , =?UTF-8?Q?Daniel_P=2E_Berrang=C3=A9?= , Eduardo Habkost , qemu-devel@nongnu.org References: <20231210-bus-v2-1-34ebf5726fa0@daynix.com> <87h6kpgrl7.fsf@pond.sub.org> <8734vzsj6k.fsf@pond.sub.org> Content-Language: en-US From: Akihiko Odaki In-Reply-To: <8734vzsj6k.fsf@pond.sub.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: none client-ip=2607:f8b0:4864:20::433; envelope-from=akihiko.odaki@daynix.com; helo=mail-pf1-x433.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_NONE=0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 2023/12/18 23:02, Markus Armbruster wrote: > Akihiko Odaki writes: > >> On 2023/12/11 15:51, Markus Armbruster wrote: >>> Akihiko Odaki writes: >>> >>>> The HotplugHandler of the machine will be used when the parent bus does >>>> not exist, but the machine may not have one. Report an error in such a >>>> case instead of aborting. >>>> >>>> Fixes: 7716b8ca74 ("qdev: HotplugHandler: Add support for unplugging BUS-less devices") >>>> Signed-off-by: Akihiko Odaki >>> >>> Do you have a reproducer for the crash? >>> >>>> --- >>>> Changes in v2: >>>> - Fixed indention. >>>> - Link to v1: https://lore.kernel.org/r/20231202-bus-v1-1-f7540e3a8d62@daynix.com >>>> --- >>>> system/qdev-monitor.c | 13 ++++++++++--- >>>> 1 file changed, 10 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c >>>> index a13db763e5..5fe5d49c20 100644 >>>> --- a/system/qdev-monitor.c >>>> +++ b/system/qdev-monitor.c >>>> @@ -927,9 +927,16 @@ void qdev_unplug(DeviceState *dev, Error **errp) >>> void qdev_unplug(DeviceState *dev, Error **errp) >>> { >>> DeviceClass *dc = DEVICE_GET_CLASS(dev); >>> HotplugHandler *hotplug_ctrl; >>> HotplugHandlerClass *hdc; >>> Error *local_err = NULL; >>> if (qdev_unplug_blocked(dev, errp)) { >>> return; >>> } >>> if (dev->parent_bus && !qbus_is_hotpluggable(dev->parent_bus)) { >>> error_setg(errp, QERR_BUS_NO_HOTPLUG, dev->parent_bus->name); >>> return; >>> } >>> if (!dc->hotpluggable) { >>> error_setg(errp, QERR_DEVICE_NO_HOTPLUG, >>> object_get_typename(OBJECT(dev))); >>> return; >>> } >>> if (!migration_is_idle() && !dev->allow_unplug_during_migration) { >>> error_setg(errp, "device_del not allowed while migrating"); >>> return; >>> } >>> >>>> qdev_hot_removed = true; >>>> hotplug_ctrl = qdev_get_hotplug_handler(dev); >>>> - /* hotpluggable device MUST have HotplugHandler, if it doesn't >>>> - * then something is very wrong with it */ >>>> - g_assert(hotplug_ctrl); >>>> + if (!hotplug_ctrl) { >>>> + /* >>>> + * hotpluggable bus MUST have HotplugHandler, if it doesn't >>>> + * then something is very wrong with it >>>> + */ >>>> + assert(!dev->parent_bus); >>>> + >>>> + error_setg(errp, "The machine does not support hotplugging for a device without parent bus"); >>>> + return; >>>> + } >>> >>> Extended version of my question above: what are the devices where >>> qdev_get_hotplug_handler(dev) returns null here? >> >> Start a VM: qemu-system-aarch64 -M virt -nographic >> Run the following on its HMP: device_del /machine/unattached/device[0] >> >> It tries to unplug cortex-a15-arm-cpu and crashes. > > This device has no parent bus (dev->parent_bus is null), but is marked > hot-pluggable (dc->hotpluggable is true). Question for somebody > familiar with the hot-plug machinery: is this sane? Setting hotpluggable false for each device without bus_type gives the same effect, but is error-prone.