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 39B53CD98F2 for ; Thu, 18 Jun 2026 11:01:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1waATv-0008CU-5t; Thu, 18 Jun 2026 07:00:23 -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 1waATs-00088V-48 for qemu-devel@nongnu.org; Thu, 18 Jun 2026 07:00:20 -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 1waATp-0002z6-Lx for qemu-devel@nongnu.org; Thu, 18 Jun 2026 07:00:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1781780416; 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=xF2fzgiS4x3BwcX0ZbEt4nOr3+zcOied7FUPcgFukPs=; b=jDZPRTAWRgnBkOpnz55HqqtnNb+MHRCLaXwS4Y9KRRTRoLDq8Z5u+0SsIlID1Sfg1AwqxN WgoZx44tc++f00JEOcUFPXIhkPF8cvgZmzhxM8tJEeEtPdrpFs8wkXgeGFYUSaDEcpYvAM 1xk8gZSRFghGehKGXzR0RBlufV7QHUE= 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-609-0towoS2gOniNs2R_EThD2w-1; Thu, 18 Jun 2026 07:00:12 -0400 X-MC-Unique: 0towoS2gOniNs2R_EThD2w-1 X-Mimecast-MFC-AGG-ID: 0towoS2gOniNs2R_EThD2w_1781780411 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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4568F180059B; Thu, 18 Jun 2026 11:00:11 +0000 (UTC) Received: from berrange.com (unknown [10.44.49.28]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 9133D1956087; Thu, 18 Jun 2026 11:00:06 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: devel@lists.libvirt.org, =?UTF-8?q?Alex=20Benn=C3=A9e?= , Christian Brauner , Markus Armbruster , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , "Dr. David Alan Gilbert" , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Subject: [PATCH v3 23/35] monitor: convert from oneshot BH to persistent BH Date: Thu, 18 Jun 2026 11:58:24 +0100 Message-ID: <20260618105836.991609-24-berrange@redhat.com> In-Reply-To: <20260618105836.991609-1-berrange@redhat.com> References: <20260618105836.991609-1-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=170.10.129.124; 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 Convert monitor_accept_input from a oneshot BH (aio_bh_schedule_oneshot) to a persistent BH (aio_bh_new + qemu_bh_schedule). Oneshot BHs cannot be cancelled, so monitor_resume() racing with destruction would schedule a callback against memory that monitor_qmp_destroy() is about to free. A persistent BH can be deleted during destruction, cancelling any pending schedule. Signed-off-by: Christian Brauner (Amutable) [DB: extracted oneshot BH conversion from larger commit] Reviewed-by: Marc-André Lureau Signed-off-by: Daniel P. Berrangé --- monitor/monitor-internal.h | 2 +- monitor/monitor.c | 25 ++++++++++++++----------- 2 files changed, 15 insertions(+), 12 deletions(-) diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h index 012d442a20..a82e1aacb6 100644 --- a/monitor/monitor-internal.h +++ b/monitor/monitor-internal.h @@ -134,7 +134,7 @@ struct Monitor { char *chardev_id; CharFrontend chr; int suspend_cnt; /* Needs to be accessed atomically */ - + QEMUBH *accept_input_bh; /* persistent BH for monitor_accept_input */ char *mon_cpu_path; QTAILQ_ENTRY(Monitor) entry; diff --git a/monitor/monitor.c b/monitor/monitor.c index bf5e8a184a..312e069bc5 100644 --- a/monitor/monitor.c +++ b/monitor/monitor.c @@ -81,6 +81,9 @@ static void monitor_finalize(Object *obj) { Monitor *mon = MONITOR(obj); + if (mon->accept_input_bh) { + qemu_bh_delete(mon->accept_input_bh); + } g_free(mon->chardev_id); g_free(mon->mon_cpu_path); qemu_chr_fe_deinit(&mon->chr, false); @@ -567,15 +570,7 @@ static void monitor_accept_input(void *opaque) void monitor_resume(Monitor *mon) { if (qatomic_dec_fetch(&mon->suspend_cnt) == 0) { - AioContext *ctx; - - if (monitor_requires_iothread(mon)) { - ctx = iothread_get_aio_context(mon_iothread); - } else { - ctx = qemu_get_aio_context(); - } - - aio_bh_schedule_oneshot(ctx, monitor_accept_input, mon); + qemu_bh_schedule(mon->accept_input_bh); } trace_monitor_suspend(mon, -1); @@ -691,6 +686,7 @@ void monitor_init_globals(void) static void monitor_complete(UserCreatable *uc, Error **errp) { Monitor *mon = MONITOR(uc); + AioContext *ctx; if (mon->chardev_id) { Chardev *chr = qemu_chr_find(mon->chardev_id); @@ -704,9 +700,16 @@ static void monitor_complete(UserCreatable *uc, Error **errp) } } - if (monitor_requires_iothread(mon) && !mon_iothread) { - mon_iothread = iothread_create("mon_iothread", &error_abort); + if (monitor_requires_iothread(mon)) { + if (!mon_iothread) { + mon_iothread = iothread_create("mon_iothread", &error_abort); + } + + ctx = iothread_get_aio_context(mon_iothread); + } else { + ctx = qemu_get_aio_context(); } + mon->accept_input_bh = aio_bh_new(ctx, monitor_accept_input, mon); } int monitor_new(MonitorOptions *opts, bool allow_hmp, Error **errp) -- 2.54.0