From: Marc Morcos <[email protected]> This fixes a thread race involving the monitor in monitor_qmp_event and monitor_qapi_event_emit .
Signed-off-by: Marc Morcos <[email protected]> Link: https://lore.kernel.org/r/[email protected] [Use QEMU_LOCK_GUARD and "continue". - Paolo] Signed-off-by: Paolo Bonzini <[email protected]> --- monitor/monitor.c | 8 ++++++-- monitor/qmp.c | 6 ++++-- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/monitor/monitor.c b/monitor/monitor.c index c5a5d308774..1273eb72605 100644 --- a/monitor/monitor.c +++ b/monitor/monitor.c @@ -346,9 +346,13 @@ static void monitor_qapi_event_emit(QAPIEvent event, QDict *qdict) } qmp_mon = container_of(mon, MonitorQMP, common); - if (qmp_mon->commands != &qmp_cap_negotiation_commands) { - qmp_send_response(qmp_mon, qdict); + { + QEMU_LOCK_GUARD(&mon->mon_lock); + if (qmp_mon->commands == &qmp_cap_negotiation_commands) { + continue; + } } + qmp_send_response(qmp_mon, qdict); } } diff --git a/monitor/qmp.c b/monitor/qmp.c index cb99a12d941..e1419a9efa3 100644 --- a/monitor/qmp.c +++ b/monitor/qmp.c @@ -462,8 +462,10 @@ static void monitor_qmp_event(void *opaque, QEMUChrEvent event) switch (event) { case CHR_EVENT_OPENED: - mon->commands = &qmp_cap_negotiation_commands; - monitor_qmp_caps_reset(mon); + WITH_QEMU_LOCK_GUARD(&mon->common.mon_lock) { + mon->commands = &qmp_cap_negotiation_commands; + monitor_qmp_caps_reset(mon); + } data = qmp_greeting(mon); qmp_send_response(mon, data); qobject_unref(data); -- 2.52.0
