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 lists1p.gnu.org (lists1p.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 A2FBFCDB46F for ; Tue, 23 Jun 2026 09:58:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wbxt3-00079a-UY; Tue, 23 Jun 2026 05:57:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wbxt1-0006xT-MV for qemu-devel@nongnu.org; Tue, 23 Jun 2026 05:57:43 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wbxsv-0003h0-OW for qemu-devel@nongnu.org; Tue, 23 Jun 2026 05:57:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782208649; 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=jObDFOXIQZ2Ilsnj5eLFY5LyP5UJd+AnpueiZqhM9Lk=; b=IqhgEw0qdWimi9UCbxIjZIGMTYc1TY4ozMjipIn49jfKjLUKVdhKfTrXz9sVsJ0zWivxjI NfCCaj/4NWPQlrvWlWYPtvWf8qrNi2EMZVH/kPapAR12GomoPBM1qK/rAlDv+AuU3qjvSq qvJK/OgmYo3qAJoUq0tOQN4t2DwQ/Sk= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-577-Q_TUCwSlPu2lU-Xn4Fci0Q-1; Tue, 23 Jun 2026 05:57:26 -0400 X-MC-Unique: Q_TUCwSlPu2lU-Xn4Fci0Q-1 X-Mimecast-MFC-AGG-ID: Q_TUCwSlPu2lU-Xn4Fci0Q_1782208645 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 21B3C1802669; Tue, 23 Jun 2026 09:57:25 +0000 (UTC) Received: from berrange.com (unknown [10.44.34.133]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B3940D6E; Tue, 23 Jun 2026 09:57:21 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: "Dr. David Alan Gilbert" , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Christian Brauner , devel@lists.libvirt.org, Markus Armbruster , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Paolo Bonzini , =?UTF-8?q?Alex=20Benn=C3=A9e?= , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Subject: [PATCH v4 24/35] monitor: reject attempts to delete the current monitor Date: Tue, 23 Jun 2026 10:55:40 +0100 Message-ID: <20260623095551.2106712-25-berrange@redhat.com> In-Reply-To: <20260623095551.2106712-1-berrange@redhat.com> References: <20260623095551.2106712-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, 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=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-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: 2.1.29 Precedence: list List-Id: qemu development 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 From: Christian Brauner If an 'object_del' command for a QMP monitor arrives targetting the current monitor, reject this request. If the current monitor is deleted, it will be impossible to send any reply and the client won't be able to remove the corresponding chardev backend. Note, it is not possible to rely on checking monitor_cur() because if 'object_del' is called via human-monitor-command, monitor_cur() will reflect the temporary HMP, not the QMP target that needs to be checked. Signed-off-by: Christian Brauner (Amutable) [DB: extracted monitor tracking from larger commit; added logic to monitor_qmp_prepare_delete to reject request] Reviewed-by: Marc-André Lureau Signed-off-by: Daniel P. Berrangé --- monitor/qmp.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/monitor/qmp.c b/monitor/qmp.c index 0e1c3eb52b..b0535dec68 100644 --- a/monitor/qmp.c +++ b/monitor/qmp.c @@ -72,6 +72,9 @@ typedef struct QMPRequest QMPRequest; QmpCommandList qmp_commands, qmp_cap_negotiation_commands; +/* Monitor being serviced by the dispatcher. Protected by BQL. */ +static MonitorQMP *qmp_dispatcher_current_mon; + OBJECT_DEFINE_TYPE(MonitorQMP, monitor_qmp, MONITOR_QMP, MONITOR); static void monitor_qmp_cleanup_req_queue_locked(MonitorQMP *mon); @@ -369,6 +372,7 @@ void coroutine_fn monitor_qmp_dispatcher_co(void *data) */ mon = req_obj->mon; + qmp_dispatcher_current_mon = mon; /* * We need to resume the monitor if handle_qmp_command() @@ -429,6 +433,7 @@ void coroutine_fn monitor_qmp_dispatcher_co(void *data) } qmp_request_free(req_obj); + qmp_dispatcher_current_mon = NULL; } qatomic_set(&qmp_dispatcher_co, NULL); } @@ -573,6 +578,11 @@ static void monitor_qmp_event(void *opaque, QEMUChrEvent event) } } +static bool monitor_qmp_dispatcher_is_servicing(MonitorQMP *mon) +{ + return qmp_dispatcher_current_mon == mon; +} + static void monitor_qmp_setup_handlers_bh(void *opaque) { MonitorQMP *mon = opaque; @@ -646,6 +656,13 @@ static void monitor_qmp_complete(UserCreatable *uc, Error **errp) static bool monitor_qmp_prepare_delete(UserCreatable *uc, Error **errp) { + MonitorQMP *qmp = MONITOR_QMP(uc); + + if (monitor_qmp_dispatcher_is_servicing(qmp)) { + error_setg(errp, "Cannot delete the current QMP monitor"); + return false; + } + error_setg(errp, "Deleting QMP monitors is not supported"); return false; } -- 2.54.0