From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48765) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cEYG9-0007gI-QL for qemu-devel@nongnu.org; Wed, 07 Dec 2016 04:11:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cEYG6-0003KH-0N for qemu-devel@nongnu.org; Wed, 07 Dec 2016 04:11:29 -0500 Date: Wed, 7 Dec 2016 09:11:18 +0000 From: "Daniel P. Berrange" Message-ID: <20161207091118.GB21167@redhat.com> Reply-To: "Daniel P. Berrange" References: <1481055300-14239-1-git-send-email-mdroth@linux.vnet.ibm.com> <1481055300-14239-2-git-send-email-mdroth@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1481055300-14239-2-git-send-email-mdroth@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH for-2.8 1/2] monitor: fix object_del for command-line-created objects List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Michael Roth Cc: qemu-devel@nongnu.org, david@gibson.dropbear.id.au, bharata.rao@gmail.com, dgilbert@redhat.com, armbru@redhat.com, Eric Blake , qemu-stable@nongnu.org On Tue, Dec 06, 2016 at 02:14:59PM -0600, Michael Roth wrote: > Currently objects specified on the command-line are only partially > cleaned up when 'object_del' is issued in either HMP or QMP: the > object itself is fully finalized, but the QemuOpts are not removed. > This results in the following behavior: > > x86_64-softmmu/qemu-system-x86_64 -monitor stdio \ > -object memory-backend-ram,id=ram1,size=256M > > QEMU 2.7.91 monitor - type 'help' for more information > (qemu) object_del ram1 > (qemu) object_del ram1 > object 'ram1' not found > (qemu) object_add memory-backend-ram,id=ram1,size=256M > Duplicate ID 'ram1' for object > Try "help object_add" for more information > > which can be an issue for use-cases like memory hotplug. > > This happens on the HMP side because hmp_object_add() attempts to > create a temporary QemuOpts entry with ID 'ram1', which ends up > conflicting with the command-line-created entry, since it was never > cleaned up during the previous hmp_object_del() call. > > We address this by adding a check in user_creatable_del(), which > is called by both qmp_object_del() and hmp_object_del() to handle > the actual object cleanup, to determine whether an option group entry > matching the object's ID is present and removing it if it is. > > Note that qmp_object_add() never attempts to create a temporary > QemuOpts entry, so it does not encounter the duplicate ID error, > which is why this isn't generally visible in libvirt. > > Cc: "Dr. David Alan Gilbert" > Cc: Markus Armbruster > Cc: Eric Blake > Cc: Daniel Berrange > Cc: qemu-stable@nongnu.org > Signed-off-by: Michael Roth > --- > qom/object_interfaces.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c > index ded4d84..23849f9 100644 > --- a/qom/object_interfaces.c > +++ b/qom/object_interfaces.c > @@ -5,6 +5,7 @@ > #include "qapi-visit.h" > #include "qapi/qobject-output-visitor.h" > #include "qapi/opts-visitor.h" > +#include "qemu/config-file.h" > > void user_creatable_complete(Object *obj, Error **errp) > { > @@ -197,6 +198,7 @@ void user_creatable_del(const char *id, Error **errp) > { > Object *container; > Object *obj; > + QemuOptsList *opt_group; > > container = object_get_objects_root(); > obj = object_resolve_path_component(container, id); > @@ -209,6 +211,15 @@ void user_creatable_del(const char *id, Error **errp) > error_setg(errp, "object '%s' is in use, can not be deleted", id); > return; > } > + > + /* if object was defined on the command-line, remove its corresponding > + * option group entry > + */ > + opt_group = qemu_find_opts_err("object", NULL); > + if (opt_group) { > + qemu_opts_del(qemu_opts_find(opt_group, id)); > + } > + > object_unparent(obj); > } Reviewed-by: Daniel P. Berrange Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://entangle-photo.org -o- http://search.cpan.org/~danberr/ :|