fix spice-server segfault on migration

spice-server tries to use the migration information without checking
whenever this is available in the first place ...

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/server/reds.c b/server/reds.c
index cdc06716..7845ebe7 100644
--- a/server/reds.c
+++ b/server/reds.c
@@ -3376,6 +3376,10 @@ static void reds_mig_switch(void)
     SpiceMsgMainMigrationSwitchHost migrate;
     RedsOutItem *item;
 
+    if (s == NULL) {
+        return;
+    }
+
     red_printf("");
     item = new_out_item(SPICE_MSG_MAIN_MIGRATE_SWITCH_HOST);