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 161C2C44529 for ; Mon, 20 Jul 2026 10:39:21 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wllOj-0003lF-MN; Mon, 20 Jul 2026 06:38:57 -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 1wllOd-0003kN-I5 for qemu-devel@nongnu.org; Mon, 20 Jul 2026 06:38:51 -0400 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 1wllOW-0008G8-Qa for qemu-devel@nongnu.org; Mon, 20 Jul 2026 06:38:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784543924; 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=zLUsY2VBLGGIb5Mf8uahKqDvB7i9l70WALZmTD9bRZE=; b=RQ7hN5VFzhU07wFtWwMBLObAYBCAcM2XL1dLfY3lr42fUgGBNR4InsSDTo1Jg9XqUxWB3s f61DB0I7LT26SCWU6izyhYX8XFXyXCHnSwalnf1zwa1AgcIUXm5sykmv9NAgY7ic8uE5Pq fqota4T2pmXMzos3QfgLA/0fCQDda3I= 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-558-j3VhDpSrPjaJ9l78zzI4tA-1; Mon, 20 Jul 2026 06:38:42 -0400 X-MC-Unique: j3VhDpSrPjaJ9l78zzI4tA-1 X-Mimecast-MFC-AGG-ID: j3VhDpSrPjaJ9l78zzI4tA_1784543921 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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 79D3C195607A; Mon, 20 Jul 2026 10:38:41 +0000 (UTC) Received: from thuth-p1g4.redhat.com (unknown [10.44.34.82]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 7FCA8158E; Mon, 20 Jul 2026 10:38:39 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org, Stefan Hajnoczi Cc: Xiangfeng Cai , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Subject: [PULL 2/7] hw/usb/hcd-xhci-pci: break host link cycle so device_finalize() runs on unplug Date: Mon, 20 Jul 2026 12:38:28 +0200 Message-ID: <20260720103833.364506-3-thuth@redhat.com> In-Reply-To: <20260720103833.364506-1-thuth@redhat.com> References: <20260720103833.364506-1-thuth@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: permerror client-ip=170.10.133.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 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=-0.01, RCVD_IN_MSPIKE_WL=-0.01, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, T_SPF_PERMERROR=0.01 autolearn=no 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: Xiangfeng Cai The xHCI PCI wrapper embeds an xhci-core child via object_initialize_child() and, in usb_xhci_pci_realize(), points the child's "host" link back at the PCI device: object_property_set_link(OBJECT(&s->xhci), "host", OBJECT(s), NULL); "host" is a DEFINE_PROP_LINK property, which qdev registers as an OBJ_PROP_LINK_STRONG link. A strong link takes a reference on its target, so this creates a refcount cycle: the PCI device owns the child, and the child's strong link pins the PCI device. On unplug (guest ACPI eject or QMP device_del), pci_qdev_unrealize() calls pc->exit() but never unrealizes the no-bus child. object_unparent() then drops only the parent/bus references, leaving the link reference in place. The PCI device stays at refcount 1 forever, so object_finalize()/device_finalize() is never reached. Symptom observed under gdb after eject: p *((Object *)dev) => ref = 1, parent = 0x0, realized = false p ((XHCIPciState *)dev)->xhci.hostOpaque => points back at dev Fix usb_xhci_pci_exit() to tear down the embedded child explicitly: unrealize it first (so the set-link-before-realize check passes), then clear the "host" link. This releases the strong reference, lets the PCI device refcount reach 0, and allows device_finalize() to run. Fixes: 8ddab8dd3d81 ("usb/hcd-xhci: Split pci wrapper for xhci base model") Signed-off-by: Xiangfeng Cai Acked-by: Marc-André Lureau Message-ID: <20260618110119.3084296-2-caixiangfeng@bytedance.com> Signed-off-by: Thomas Huth --- hw/usb/hcd-xhci-pci.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/hw/usb/hcd-xhci-pci.c b/hw/usb/hcd-xhci-pci.c index c5446a4a5e1..b124251ae33 100644 --- a/hw/usb/hcd-xhci-pci.c +++ b/hw/usb/hcd-xhci-pci.c @@ -196,6 +196,18 @@ static void usb_xhci_pci_exit(PCIDevice *dev) && dev->msix_entry_used) { msix_uninit(dev, &s->xhci.mem, &s->xhci.mem); } + /* + * The embedded xhci-core child holds a strong "host" link back to this + * PCI device (set in usb_xhci_pci_realize()), forming a refcount cycle: + * the PCI device owns the child, and the child's strong link pins the PCI + * device. On unplug, object_unparent() only drops the parent/bus refs, so + * the link ref keeps this device at refcount 1 forever and + * device_finalize() never runs. Unrealize the child first (so the + * realized-check in set_link passes), then clear the link to break the + * cycle. + */ + qdev_unrealize(DEVICE(&s->xhci)); + object_property_set_link(OBJECT(&s->xhci), "host", NULL, &error_abort); } static const VMStateDescription vmstate_xhci_pci = { -- 2.55.0