From nobody Sun Feb 8 21:33:21 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; envelope-from=libvir-list-bounces@redhat.com; helo=mx1.redhat.com; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=libvir-list-bounces@redhat.com; dmarc=pass(p=none dis=none) header.from=redhat.com Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mx.zohomail.com with SMTPS id 1553003395841558.4085238348005; Tue, 19 Mar 2019 06:49:55 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0B78881E10; Tue, 19 Mar 2019 13:49:54 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D3E49601A4; Tue, 19 Mar 2019 13:49:53 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 95CA43FA4A; Tue, 19 Mar 2019 13:49:53 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id x2JDnhKh012120 for ; Tue, 19 Mar 2019 09:49:43 -0400 Received: by smtp.corp.redhat.com (Postfix) id E15AE282FC; Tue, 19 Mar 2019 13:49:43 +0000 (UTC) Received: from moe.brq.redhat.com (unknown [10.43.2.30]) by smtp.corp.redhat.com (Postfix) with ESMTP id 688BE19C71 for ; Tue, 19 Mar 2019 13:49:43 +0000 (UTC) From: Michal Privoznik To: libvir-list@redhat.com Date: Tue, 19 Mar 2019 14:49:35 +0100 Message-Id: <66da3d9965c32581adcb331c1c674a219e137fdd.1553003328.git.mprivozn@redhat.com> In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-loop: libvir-list@redhat.com Subject: [libvirt] [PATCH 2/3] virDomainObjListAddLocked: Produce better error message than 'Duplicate key' X-BeenThere: libvir-list@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Development discussions about the libvirt library & tools List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: quoted-printable Sender: libvir-list-bounces@redhat.com Errors-To: libvir-list-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 19 Mar 2019 13:49:54 +0000 (UTC) Content-Type: text/plain; charset="utf-8" If there are two concurrent threads, one of which is removing a domain from the list and the other is trying to add it back they may serialize in the following order: 1) vm->removing is set and @vm is unlocked. 2) The tread that's trying to add the domain onto the list locks the list and tries to find, if the domain already exists. 3) Our lookup functions say it doesn't, so the thread proceeds to virHashAddEntry() which fails with 'Duplicate key' error. This is obviously not helpful error message at all. The problem lies in our lookup functions (virDomainObjListFindByUUIDLocked() and virDomainObjListFindByNameLocked()) which return NULL even if the object is still on the list. They do this so that the object is not mistakenly looked up by some driver. The fix consists of moving 'removing' check one level up and thus allowing virDomainObjListAddLocked() to produce meaningful error message. Signed-off-by: Michal Privoznik Reviewed-by: Cole Robinson --- src/conf/virdomainobjlist.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) diff --git a/src/conf/virdomainobjlist.c b/src/conf/virdomainobjlist.c index 3631cf16d0..23734ad815 100644 --- a/src/conf/virdomainobjlist.c +++ b/src/conf/virdomainobjlist.c @@ -141,14 +141,9 @@ virDomainObjListFindByUUIDLocked(virDomainObjListPtr d= oms, =20 virUUIDFormat(uuid, uuidstr); obj =3D virHashLookup(doms->objs, uuidstr); - virObjectRef(obj); if (obj) { + virObjectRef(obj); virObjectLock(obj); - if (obj->removing) { - virObjectUnlock(obj); - virObjectUnref(obj); - obj =3D NULL; - } } return obj; } @@ -172,6 +167,12 @@ virDomainObjListFindByUUID(virDomainObjListPtr doms, obj =3D virDomainObjListFindByUUIDLocked(doms, uuid); virObjectRWUnlock(doms); =20 + if (obj && obj->removing) { + virObjectUnlock(obj); + virObjectUnref(obj); + obj =3D NULL; + } + return obj; } =20 @@ -183,14 +184,9 @@ virDomainObjListFindByNameLocked(virDomainObjListPtr d= oms, virDomainObjPtr obj; =20 obj =3D virHashLookup(doms->objsName, name); - virObjectRef(obj); if (obj) { + virObjectRef(obj); virObjectLock(obj); - if (obj->removing) { - virObjectUnlock(obj); - virObjectUnref(obj); - obj =3D NULL; - } } return obj; } @@ -214,6 +210,12 @@ virDomainObjListFindByName(virDomainObjListPtr doms, obj =3D virDomainObjListFindByNameLocked(doms, name); virObjectRWUnlock(doms); =20 + if (obj && obj->removing) { + virObjectUnlock(obj); + virObjectUnref(obj); + obj =3D NULL; + } + return obj; } =20 @@ -285,8 +287,13 @@ virDomainObjListAddLocked(virDomainObjListPtr doms, =20 /* See if a VM with matching UUID already exists */ if ((vm =3D virDomainObjListFindByUUIDLocked(doms, def->uuid))) { - /* UUID matches, but if names don't match, refuse it */ - if (STRNEQ(vm->def->name, def->name)) { + if (vm->removing) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("domain '%s' is already being removed"), + vm->def->name); + goto error; + } else if (STRNEQ(vm->def->name, def->name)) { + /* UUID matches, but if names don't match, refuse it */ virUUIDFormat(vm->def->uuid, uuidstr); virReportError(VIR_ERR_OPERATION_FAILED, _("domain '%s' is already defined with uuid %s"= ), --=20 2.19.2 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list