From: Maxim Levitsky Date: Tue, 6 Oct 2020 12:38:58 +0000 (+0200) Subject: device_core: use drain_call_rcu in in qmp_device_add X-Git-Tag: upstream/4.2.1~75 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5c4e6fa486edc11067d8023e203ffab07096d25b;p=tools%2Fqemu-arm-static.git device_core: use drain_call_rcu in in qmp_device_add Git-commit: 7bed89958bfbf40df9ca681cefbdca63abdde39d References: bsc#1184574 Soon, a device removal might only happen on RCU callback execution. This is okay for device-del which provides a DEVICE_DELETED event, but not for the failure case of device-add. To avoid changing monitor semantics, just drain all pending RCU callbacks on error. Signed-off-by: Maxim Levitsky Suggested-by: Stefan Hajnoczi Reviewed-by: Stefan Hajnoczi Message-Id: <20200913160259.32145-4-mlevitsk@redhat.com> [Don't use it in qmp_device_del. - Paolo] Signed-off-by: Paolo Bonzini Signed-off-by: Lin Ma --- diff --git a/qdev-monitor.c b/qdev-monitor.c index dc0323051..ade59c9ec 100644 --- a/qdev-monitor.c +++ b/qdev-monitor.c @@ -796,6 +796,18 @@ void qmp_device_add(QDict *qdict, QObject **ret_data, Error **errp) return; } dev = qdev_device_add(opts, &local_err); + + /* + * Drain all pending RCU callbacks. This is done because + * some bus related operations can delay a device removal + * (in this case this can happen if device is added and then + * removed due to a configuration error) + * to a RCU callback, but user might expect that this interface + * will finish its job completely once qmp command returns result + * to the user + */ + drain_call_rcu(); + if (!dev) { error_propagate(errp, local_err); qemu_opts_del(opts);