migration: Fix early failure cleanup

Avoid crash in cleanup after a very early migration failure
(possibly due to my 688a3dcba980bf01344a  'Route errors down ...')

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20180212160340.15333-2-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>

diff --git a/migration/ram.c b/migration/ram.c
index 8333d8e..7095c10 100644 (file)
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1602,11 +1602,13 @@ static void xbzrle_load_cleanup(void)
 
 static void ram_state_cleanup(RAMState **rsp)
 {
-    migration_page_queue_free(*rsp);
-    qemu_mutex_destroy(&(*rsp)->bitmap_mutex);
-    qemu_mutex_destroy(&(*rsp)->src_page_req_mutex);
-    g_free(*rsp);
-    *rsp = NULL;
+    if (*rsp) {
+        migration_page_queue_free(*rsp);
+        qemu_mutex_destroy(&(*rsp)->bitmap_mutex);
+        qemu_mutex_destroy(&(*rsp)->src_page_req_mutex);
+        g_free(*rsp);
+        *rsp = NULL;
+    }
 }
 
 static void xbzrle_cleanup(void)