[Qemu-devel] [PATCH] Migration+TLS: Fix crash due to double cleanup

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

During a TLS connect we see:
  migration_channel_connect calls
  migration_tls_channel_connect
  (calls after TLS setup)
  migration_channel_connect

My previous error handling fix made migration_channel_connect
call migrate_fd_connect in all cases; unfortunately the above
means it gets called twice and crashes doing double cleanup.

Fixes: 688a3dcba98

Reported-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/channel.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/migration/channel.c b/migration/channel.c
index c5eaf0fa0e..7a32b5aca4 100644
--- a/migration/channel.c
+++ b/migration/channel.c
@@ -71,6 +71,15 @@ void migration_channel_connect(MigrationState *s,
             !object_dynamic_cast(OBJECT(ioc),
                                  TYPE_QIO_CHANNEL_TLS)) {
             migration_tls_channel_connect(s, ioc, hostname, &error);
+
+            if (!error) {
+                /* tls_channel_connect will call back to this
+                 * function after the TLS handshake,
+                 * so we mustn't call migrate_fd_connect until then
+                 */
+
+                return;
+            }
         } else {
             QEMUFile *f = qemu_fopen_channel_output(ioc);
 
-- 
2.17.0