We found a exception when libvirt occurrs segmentation fault. thread 1 is waiting object lock in qemuConnectMonitor, qemu process exits and sends EOF event as well, so thread 2 invokes qemuMonitorLastError but pointer mon is NULL. Signed-off-by: Xu Yandong <xuyandong2(a)huawei.com&gt; --- src/qemu/qemu_monitor.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c index aa230b3306..28f18391a5 100644 --- a/src/qemu/qemu_monitor.c +++ b/src/qemu/qemu_monitor.c @@ -1103,7 +1103,7 @@ qemuMonitorSend(qemuMonitorPtr mon, virErrorPtr qemuMonitorLastError(qemuMonitorPtr mon) { - if (mon->lastError.code == VIR_ERR_OK) + if (!mon || mon->lastError.code == VIR_ERR_OK) return NULL; return virErrorCopyNew(&mon->lastError);