[PATCH 5/7] migration: Display error in query-migrate irrelevant of status

[Peter Xu <peterx@redhat.com>]

Display it as long as being set, irrelevant of FAILED status.  E.g., it may
also be applicable to PAUSED stage of postcopy, to provide hint on what has
gone wrong.

The error_mutex seems to be overlooked when referencing the error, add it
to be very safe.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/migration.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 234dd3601d..7455353918 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1033,9 +1033,6 @@ static void fill_source_migration_info(MigrationInfo *info)
         break;
     case MIGRATION_STATUS_FAILED:
         info->has_status = true;
-        if (s->error) {
-            info->error_desc = g_strdup(error_get_pretty(s->error));
-        }
         break;
     case MIGRATION_STATUS_CANCELLED:
         info->has_status = true;
@@ -1045,6 +1042,11 @@ static void fill_source_migration_info(MigrationInfo *info)
         break;
     }
     info->status = state;
+
+    QEMU_LOCK_GUARD(&s->error_mutex);
+    if (s->error) {
+        info->error_desc = g_strdup(error_get_pretty(s->error));
+    }
 }
 
 static void fill_destination_migration_info(MigrationInfo *info)
-- 
2.41.0