commit 03e8d5fb54c7c897225ed9ea56d83b894930f144
Author: Peter Krempa <pkrempa@redhat.com>
Date:   Thu Apr 7 12:50:15 2016 +0200

    qemu: perf: Fix crash/memory corruption on failed VM start
    
    The new perf code didn't bother to clear a pointer in 'priv' causing a
    double free or other memory corruption goodness if a VM failed to start.
    
    Clear the pointer after freeing the memory.
    
    Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1324757

Index: libvirt-1.3.3/src/qemu/qemu_process.c
===================================================================
--- libvirt-1.3.3.orig/src/qemu/qemu_process.c
+++ libvirt-1.3.3/src/qemu/qemu_process.c
@@ -3444,6 +3444,7 @@ qemuDomainPerfRestart(virDomainObjPtr vm
 
  cleanup:
     virPerfFree(priv->perf);
+    priv->perf = NULL;
     return -1;
 }
 
@@ -5959,6 +5960,7 @@ void qemuProcessStop(virQEMUDriverPtr dr
     virCgroupFree(&priv->cgroup);
 
     virPerfFree(priv->perf);
+    priv->perf = NULL;
 
     qemuProcessRemoveDomainStatus(driver, vm);