From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56279) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XtxE2-0005QK-Em for qemu-devel@nongnu.org; Thu, 27 Nov 2014 06:27:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XtxDt-0007ej-D7 for qemu-devel@nongnu.org; Thu, 27 Nov 2014 06:27:06 -0500 Received: from mail-wg0-x22c.google.com ([2a00:1450:400c:c00::22c]:43012) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XtxDt-0007eX-1d for qemu-devel@nongnu.org; Thu, 27 Nov 2014 06:26:57 -0500 Received: by mail-wg0-f44.google.com with SMTP id b13so6214353wgh.3 for ; Thu, 27 Nov 2014 03:26:56 -0800 (PST) Message-ID: <1417087560.2807.24.camel@localhost.localdomain> From: Marcel Apfelbaum Date: Thu, 27 Nov 2014 13:26:00 +0200 In-Reply-To: <1417086688.2807.19.camel@localhost.localdomain> References: <1417002601-20799-1-git-send-email-marcel.a@redhat.com> <20141126130528.50835019@redhat.com> <1417086688.2807.19.camel@localhost.localdomain> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] hmp: fix regression of HMP device_del auto-completion Reply-To: marcel.a@redhat.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Luiz Capitulino , Peter Maydell Cc: "qemu-devel@nongnu.org" On Thu, 2014-11-27 at 13:11 +0200, Marcel Apfelbaum wrote: > On Wed, 2014-11-26 at 13:05 -0500, Luiz Capitulino wrote: > > On Wed, 26 Nov 2014 13:50:01 +0200 > > Marcel Apfelbaum wrote: > > > > > The commits: > > > - 6a1fa9f5 (monitor: add del completion for peripheral device) > > > - 66e56b13 (qdev: add qdev_build_hotpluggable_device_list helper) > > > > > > cause a QEMU crash when trying to use HMP device_del auto-completion. > > > It can be easily reproduced by: > > > -enable-kvm ~/images/fedora.qcow2 -monitor stdio -device virtio-net-pci,id=vnet > > > > > > (qemu) device_del > > > /home/mapfelba/git/upstream/qemu/hw/core/qdev.c:941:qdev_build_hotpluggable_device_list: Object 0x7f6ce04e4fe0 is not an instance of type device > > > Aborted (core dumped) > > > > > > The root cause is qdev_build_hotpluggable_device_list going recursively over > > > all peripherals and their children assuming all are devices. It doesn't work > > > since PCI devices have at least on child which is a memory region (bus master). > > > > > > Solved by observing that all devices appear as direct children of > > > /machine/peripheral container. No need of going recursively > > > over all the children. > > > > > > Signed-off-by: Marcel Apfelbaum > > > > Peter, can you apply this patch directly to master to avoid me a pull > > request? Maybe it's a good idea to wait until tomorrow for more > > reviewers though. > Speaking of reviewers, I double checked the patch and indeed it solves > the crash, but the original patch has another semantic error. > It looks for hot-pluggable device and not *hot-plugged* ones. Thinking further, this is not fully true, we can hot-unplugged devices that weren't hot-plugged. We have only a specific problem/bug with pci-2-pci bridge that is hotpluggable, but can be hot-unpluged *only if* was hot-plugged. Other devices do not have this limitation. > > I'll try to come with a solution fast. It should be a "hot-plugged" property somewhere... No need for a solution now, the above bug can wait for 2.3, the crash is more important. Please pull the patch for 2.2 Thanks, Marcel > > Thanks, > Marcel > > > > > > Marcel, thanks a lot for taking care of this! > > > > > --- > > > hw/core/qdev.c | 12 ++++++++++-- > > > include/hw/qdev-core.h | 2 +- > > > monitor.c | 11 ++++------- > > > 3 files changed, 15 insertions(+), 10 deletions(-) > > > > > > diff --git a/hw/core/qdev.c b/hw/core/qdev.c > > > index 413b413..35fd00d 100644 > > > --- a/hw/core/qdev.c > > > +++ b/hw/core/qdev.c > > > @@ -935,7 +935,7 @@ void qdev_alias_all_properties(DeviceState *target, Object *source) > > > } while (class != object_class_by_name(TYPE_DEVICE)); > > > } > > > > > > -int qdev_build_hotpluggable_device_list(Object *obj, void *opaque) > > > +static int qdev_add_hotpluggable_device(Object *obj, void *opaque) > > > { > > > GSList **list = opaque; > > > DeviceState *dev = DEVICE(obj); > > > @@ -944,10 +944,18 @@ int qdev_build_hotpluggable_device_list(Object *obj, void *opaque) > > > *list = g_slist_append(*list, dev); > > > } > > > > > > - object_child_foreach(obj, qdev_build_hotpluggable_device_list, opaque); > > > return 0; > > > } > > > > > > +GSList *qdev_build_hotpluggable_device_list(Object *peripheral) > > > +{ > > > + GSList *list = NULL; > > > + > > > + object_child_foreach(peripheral, qdev_add_hotpluggable_device, &list); > > > + > > > + return list; > > > +} > > > + > > > static bool device_get_realized(Object *obj, Error **errp) > > > { > > > DeviceState *dev = DEVICE(obj); > > > diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h > > > index d3a2940..589bbe7 100644 > > > --- a/include/hw/qdev-core.h > > > +++ b/include/hw/qdev-core.h > > > @@ -365,7 +365,7 @@ extern int qdev_hotplug; > > > > > > char *qdev_get_dev_path(DeviceState *dev); > > > > > > -int qdev_build_hotpluggable_device_list(Object *obj, void *opaque); > > > +GSList *qdev_build_hotpluggable_device_list(Object *peripheral); > > > > > > void qbus_set_hotplug_handler(BusState *bus, DeviceState *handler, > > > Error **errp); > > > diff --git a/monitor.c b/monitor.c > > > index fa00594..f1031a1 100644 > > > --- a/monitor.c > > > +++ b/monitor.c > > > @@ -4321,17 +4321,14 @@ void object_add_completion(ReadLineState *rs, int nb_args, const char *str) > > > static void peripheral_device_del_completion(ReadLineState *rs, > > > const char *str, size_t len) > > > { > > > - Object *peripheral; > > > - GSList *list = NULL, *item; > > > + Object *peripheral = container_get(qdev_get_machine(), "/peripheral"); > > > + GSList *list, *item; > > > > > > - peripheral = object_resolve_path("/machine/peripheral/", NULL); > > > - if (peripheral == NULL) { > > > + list = qdev_build_hotpluggable_device_list(peripheral); > > > + if (!list) { > > > return; > > > } > > > > > > - object_child_foreach(peripheral, qdev_build_hotpluggable_device_list, > > > - &list); > > > - > > > for (item = list; item; item = g_slist_next(item)) { > > > DeviceState *dev = item->data; > > > > > > > > > > >