Denis Plotnikov <den-plotni...@yandex-team.ru> writes: > This is needed to keep sending DEVICE_DELETED events on qemu cleanup. > The event may happen in the rcu thread and we're going to flush the rcu queue > explicitly before qemu exiting in the next patch. So move the monitor > destruction to the very end of qemu cleanup to be able to send all the events. > > Signed-off-by: Denis Plotnikov <den-plotni...@yandex-team.ru> > --- > monitor/monitor.c | 6 ++++++ > softmmu/runstate.c | 2 +- > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/monitor/monitor.c b/monitor/monitor.c > index 21c7a68758f5..b04ae4850db2 100644 > --- a/monitor/monitor.c > +++ b/monitor/monitor.c > @@ -605,11 +605,17 @@ void monitor_data_init(Monitor *mon, bool is_qmp, bool > skip_flush, > mon->outbuf = g_string_new(NULL); > mon->skip_flush = skip_flush; > mon->use_io_thread = use_io_thread; > + /* > + * take an extra ref to prevent monitor's chardev > + * from destroying in qemu_chr_cleanup() > + */ > + object_ref(OBJECT(mon->chr.chr));
I'm not sure we need the comment in the long run. Taking a reference changes mon->chr.chr from soft reference to hard reference. Feels right to me. Note that mon->chr.chr isn't set here, but earlier. Unlike the other parts of @mon. Because of this it starts as a soft reference, and hardens only here. It's set in three places: 1. monitor_init_hmp(): if (!qemu_chr_fe_init(&mon->common.chr, chr, errp)) { g_free(mon); return; } monitor_data_init(&mon->common, false, false, false); 2. monitor_init_qmp(): if (!qemu_chr_fe_init(&mon->common.chr, chr, errp)) { g_free(mon); return; } qemu_chr_fe_set_echo(&mon->common.chr, true); /* Note: we run QMP monitor in I/O thread when @chr supports that */ monitor_data_init(&mon->common, true, false, qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_GCONTEXT)); 3. qmp_human_monitor_command() MonitorHMP hmp = {}; monitor_data_init(&hmp.common, false, true, false); hmp.common.chr.chr remains null here. Works, because object_ref(OBJECT(NULL)) and object_unref(OBJECT(NULL)) do nothing. Slightly cleaner, I think: pass the character device as an argument to monitor_data_init(), take a reference and store it in mon->chr.chr there. > } > > void monitor_data_destroy(Monitor *mon) > { > g_free(mon->mon_cpu_path); > + object_unref(OBJECT(mon->chr.chr)); > qemu_chr_fe_deinit(&mon->chr, false); > if (monitor_is_qmp(mon)) { > monitor_data_destroy_qmp(container_of(mon, MonitorQMP, common)); > diff --git a/softmmu/runstate.c b/softmmu/runstate.c > index 10d9b7365aa7..8d29dd2c00e2 100644 > --- a/softmmu/runstate.c > +++ b/softmmu/runstate.c > @@ -819,8 +819,8 @@ void qemu_cleanup(void) > tpm_cleanup(); > net_cleanup(); > audio_cleanup(); > - monitor_cleanup(); > qemu_chr_cleanup(); > user_creatable_cleanup(); > + monitor_cleanup(); > /* TODO: unref root container, check all devices are ok */ > } Monitor cleanup now runs with character devices that have been "unparented" from the QOM tree. Paolo, is that okay?