Merge tag 'tracing-pull-request' into staging

# gpg: Signature made Fri 12 May 2017 10:38:07 AM EDT
# gpg:                using RSA key 0x9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* tag 'tracing-pull-request':
  trace: add sanity check
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

qom/cpu.c

@@ -382,6 +382,7 @@ static void cpu_common_unrealizefn(DeviceState *dev, Error **errp)
 
 static void cpu_common_initfn(Object *obj)
 {
+    uint32_t count;
     CPUState *cpu = CPU(obj);
     CPUClass *cc = CPU_GET_CLASS(obj);
 
@@ -396,7 +397,10 @@ static void cpu_common_initfn(Object *obj)
     QTAILQ_INIT(&cpu->breakpoints);
     QTAILQ_INIT(&cpu->watchpoints);
 
-    cpu->trace_dstate = bitmap_new(trace_get_vcpu_event_count());
+    count = trace_get_vcpu_event_count();
+    if (count) {
+        cpu->trace_dstate = bitmap_new(count);
+    }
 
     cpu_exec_initfn(cpu);
 }