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 B3A6AD1D482 for ; Thu, 8 Jan 2026 17:06:20 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vdtQg-0003rv-U8; Thu, 08 Jan 2026 12:04:10 -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 1vdtQd-0003l7-2E for qemu-rust@nongnu.org; Thu, 08 Jan 2026 12:04:07 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vdtQb-0006rO-Kv for qemu-rust@nongnu.org; Thu, 08 Jan 2026 12:04:06 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1767891845; 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=VtFPI6vVXa2ox707p91yDXfVumBlXkpusbUwLIynWCc=; b=JrThNT27O5cfPhC6jfS4dyUZgijE0ZeGGo38i+R2ZI3W7xI8YzF11R+4FZDGeDbuXxjejR EK3CDSHYAMxl69YxnNBzf5IZDFG0FY6y8mCsQjSmNoGKa+5tsd9J3tIlO3bJCoZivscAKN EOlcGLLLuPq+qEa6s+FJ4PGg0KgVqCY= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-542-_VYh9_zhNe-y6nSlJbwTsQ-1; Thu, 08 Jan 2026 12:04:00 -0500 X-MC-Unique: _VYh9_zhNe-y6nSlJbwTsQ-1 X-Mimecast-MFC-AGG-ID: _VYh9_zhNe-y6nSlJbwTsQ_1767891838 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8D8BB1956095; Thu, 8 Jan 2026 17:03:58 +0000 (UTC) Received: from toolbx.redhat.com (unknown [10.42.28.44]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C3A2C19560B4; Thu, 8 Jan 2026 17:03:54 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Manos Pitsidianakis , Hanna Reitz , Gerd Hoffmann , Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Christian Schoenebeck , "Dr. David Alan Gilbert" , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , devel@lists.libvirt.org, qemu-block@nongnu.org, qemu-rust@nongnu.org, Markus Armbruster , Stefan Weil , Kevin Wolf , Richard Henderson Subject: [PATCH v5 03/24] monitor: initialize global data from a constructor Date: Thu, 8 Jan 2026 17:03:17 +0000 Message-ID: <20260108170338.2693853-4-berrange@redhat.com> In-Reply-To: <20260108170338.2693853-1-berrange@redhat.com> References: <20260108170338.2693853-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-rust@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: QEMU Rust-related patches and discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-rust-bounces+qemu-rust=archiver.kernel.org@nongnu.org Sender: qemu-rust-bounces+qemu-rust=archiver.kernel.org@nongnu.org Some monitor functions, most notably, monitor_cur() rely on global data being initialized by 'monitor_init_globals()'. The latter is called relatively late in startup. If code triggers error_report() before monitor_init_globals() is called, QEMU will abort when accessing the uninitialized monitor mutex. The critical monitor global data must be initialized from a constructor function, to improve the guarantee that it is done before any possible calls to monitor_cur(). Not only that, but the constructor must be marked to run before the default constructor in case any of them trigger error reporting. Note in particular that the RCU constructor will spawn a background thread so we might even have non-constructor QEMU code running concurrently with other constructors. As a general note, constructors should be extrememly careful about what QEMU code they invoke, as it cannot be guaranteed that the process is fully initialized and so not all normal QEMU API rules apply. Reviewed-by: Richard Henderson Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Markus Armbruster Fixes: e69ee454b5f9 (monitor: Make current monitor a per-coroutine property) Signed-off-by: Daniel P. Berrangé --- monitor/monitor.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/monitor/monitor.c b/monitor/monitor.c index 1273eb7260..dd2c45ded0 100644 --- a/monitor/monitor.c +++ b/monitor/monitor.c @@ -708,18 +708,22 @@ void monitor_cleanup(void) } } -static void monitor_qapi_event_init(void) +/* + * Initialize static vars that have no deps on external + * module initialization, and are required for external + * functions to call things like monitor_cur() + */ +static void __attribute__((__constructor__(QEMU_CONSTRUCTOR_EARLY))) +monitor_init_static(void) { + qemu_mutex_init(&monitor_lock); + coroutine_mon = g_hash_table_new(NULL, NULL); monitor_qapi_event_state = g_hash_table_new(qapi_event_throttle_hash, qapi_event_throttle_equal); } void monitor_init_globals(void) { - monitor_qapi_event_init(); - qemu_mutex_init(&monitor_lock); - coroutine_mon = g_hash_table_new(NULL, NULL); - /* * The dispatcher BH must run in the main loop thread, since we * have commands assuming that context. It would be nice to get -- 2.52.0