From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49514) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cgvId-0000fR-27 for qemu-devel@nongnu.org; Thu, 23 Feb 2017 10:27:20 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cgvIZ-0001Me-OO for qemu-devel@nongnu.org; Thu, 23 Feb 2017 10:27:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50030) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cgvIZ-0001MM-G9 for qemu-devel@nongnu.org; Thu, 23 Feb 2017 10:27:15 -0500 Date: Thu, 23 Feb 2017 15:27:10 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20170223152709.GD2383@work-vm> References: <1487009088-23891-1-git-send-email-ashijeetacharya@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1487009088-23891-1-git-send-email-ashijeetacharya@gmail.com> Subject: Re: [Qemu-devel] [PATCH v4] migrate: Introduce a 'dc->vmsd' check to avoid segfault for --only-migratable List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Ashijeet Acharya Cc: quintela@redhat.com, peter.maydell@linaro.org, pbonzini@redhat.com, qemu-devel@nongnu.org * Ashijeet Acharya (ashijeetacharya@gmail.com) wrote: > Commit a3a3d8c7 introduced a segfault bug while checking for > 'dc->vmsd->unmigratable' which caused QEMU to crash when trying to add > devices which do no set their 'dc->vmsd' yet while initialization. > Place a 'dc->vmsd' check prior to it so that we do not segfault for > such devices. > > NOTE: This doesn't compromise the functioning of --only-migratable > option as all the unmigratable devices do set their 'dc->vmsd'. > > Introduce a new function check_migratable() and move the > only_migratable check inside it, also use stubs to avoid user-mode qemu > build failures. > > Signed-off-by: Ashijeet Acharya Yep, I think that should work. Reviewed-by: Dr. David Alan Gilbert > --- > Changes in v4: > - introduce new check_migratable() function and use stubs > Changes is v3: > - move only_migratable check inside device_set_realized() to avoid code > - duplication > - I have dropped Juan's R-b tag for this one > Changes in v2: > - place dc->vmsd check in hw/usb/bus.c as well > --- > hw/core/qdev.c | 7 +++++++ > hw/usb/bus.c | 19 ------------------- > include/migration/migration.h | 3 +++ > migration/migration.c | 15 +++++++++++++++ > qdev-monitor.c | 9 --------- > stubs/vmstate.c | 6 ++++++ > 6 files changed, 31 insertions(+), 28 deletions(-) > > diff --git a/hw/core/qdev.c b/hw/core/qdev.c > index 5783442..4f49cfe 100644 > --- a/hw/core/qdev.c > +++ b/hw/core/qdev.c > @@ -37,6 +37,7 @@ > #include "hw/boards.h" > #include "hw/sysbus.h" > #include "qapi-event.h" > +#include "migration/migration.h" > > int qdev_hotplug = 0; > static bool qdev_hot_added = false; > @@ -889,6 +890,7 @@ static void device_set_realized(Object *obj, bool value, Error **errp) > Error *local_err = NULL; > bool unattached_parent = false; > static int unattached_count; > + int ret; > > if (dev->hotplugged && !dc->hotpluggable) { > error_setg(errp, QERR_DEVICE_NO_HOTPLUG, object_get_typename(obj)); > @@ -896,6 +898,11 @@ static void device_set_realized(Object *obj, bool value, Error **errp) > } > > if (value && !dev->realized) { > + ret = check_migratable(obj, &local_err); > + if (ret < 0) { > + goto fail; > + } > + > if (!obj->parent) { > gchar *name = g_strdup_printf("device[%d]", unattached_count++); > > diff --git a/hw/usb/bus.c b/hw/usb/bus.c > index 1dcc35c..25913ad 100644 > --- a/hw/usb/bus.c > +++ b/hw/usb/bus.c > @@ -8,7 +8,6 @@ > #include "monitor/monitor.h" > #include "trace.h" > #include "qemu/cutils.h" > -#include "migration/migration.h" > > static void usb_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent); > > @@ -687,8 +686,6 @@ USBDevice *usbdevice_create(const char *cmdline) > const char *params; > int len; > USBDevice *dev; > - ObjectClass *klass; > - DeviceClass *dc; > > params = strchr(cmdline,':'); > if (params) { > @@ -723,22 +720,6 @@ USBDevice *usbdevice_create(const char *cmdline) > return NULL; > } > > - klass = object_class_by_name(f->name); > - if (klass == NULL) { > - error_report("Device '%s' not found", f->name); > - return NULL; > - } > - > - dc = DEVICE_CLASS(klass); > - > - if (only_migratable) { > - if (dc->vmsd->unmigratable) { > - error_report("Device %s is not migratable, but --only-migratable " > - "was specified", f->name); > - return NULL; > - } > - } > - > if (f->usbdevice_init) { > dev = f->usbdevice_init(bus, params); > } else { > diff --git a/include/migration/migration.h b/include/migration/migration.h > index af9135f..a6868cd 100644 > --- a/include/migration/migration.h > +++ b/include/migration/migration.h > @@ -22,6 +22,7 @@ > #include "qapi-types.h" > #include "exec/cpu-common.h" > #include "qemu/coroutine_int.h" > +#include "qom/object.h" > > #define QEMU_VM_FILE_MAGIC 0x5145564d > #define QEMU_VM_FILE_VERSION_COMPAT 0x00000002 > @@ -305,6 +306,8 @@ int migrate_add_blocker(Error *reason, Error **errp); > */ > void migrate_del_blocker(Error *reason); > > +int check_migratable(Object *obj, Error **err); > + > bool migrate_postcopy_ram(void); > bool migrate_zero_blocks(void); > > diff --git a/migration/migration.c b/migration/migration.c > index 2766d2f..00b33f3 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -1146,6 +1146,21 @@ void migrate_del_blocker(Error *reason) > migration_blockers = g_slist_remove(migration_blockers, reason); > } > > +int check_migratable(Object *obj, Error **err) > +{ > + DeviceClass *dc = DEVICE_GET_CLASS(obj); > + if (only_migratable && dc->vmsd) { > + if (dc->vmsd->unmigratable) { > + error_setg(err, "Device %s is not migratable, but " > + "--only-migratable was specified", > + object_get_typename(obj)); > + return -1; > + } > + } > + > + return 0; > +} > + > void qmp_migrate_incoming(const char *uri, Error **errp) > { > Error *local_err = NULL; > diff --git a/qdev-monitor.c b/qdev-monitor.c > index 549f45f..5f2fcdf 100644 > --- a/qdev-monitor.c > +++ b/qdev-monitor.c > @@ -29,7 +29,6 @@ > #include "qemu/error-report.h" > #include "qemu/help_option.h" > #include "sysemu/block-backend.h" > -#include "migration/migration.h" > > /* > * Aliases were a bad idea from the start. Let's keep them > @@ -579,14 +578,6 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp) > return NULL; > } > > - if (only_migratable) { > - if (dc->vmsd->unmigratable) { > - error_setg(errp, "Device %s is not migratable, but " > - "--only-migratable was specified", driver); > - return NULL; > - } > - } > - > /* find bus */ > path = qemu_opt_get(opts, "bus"); > if (path != NULL) { > diff --git a/stubs/vmstate.c b/stubs/vmstate.c > index 6590627..5a71770 100644 > --- a/stubs/vmstate.c > +++ b/stubs/vmstate.c > @@ -1,6 +1,7 @@ > #include "qemu/osdep.h" > #include "qemu-common.h" > #include "migration/vmstate.h" > +#include "migration/migration.h" > > const VMStateDescription vmstate_dummy = {}; > > @@ -18,3 +19,8 @@ void vmstate_unregister(DeviceState *dev, > void *opaque) > { > } > + > +int check_migratable(Object *obj, Error **err) > +{ > + return 0; > +} > -- > 2.6.2 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK