migration: Don't do migrate cleanup if during postcopy resume
Below process could crash qemu with postcopy recovery:
1. (hmp) migrate -d ..
2. (hmp) migrate_start_postcopy
3. [network down, postcopy paused]
4. (hmp) migrate -r $WRONG_PORT
when try the recover on an invalid $WRONG_PORT, cleanup_bh will be cleared
5. (hmp) migrate -r $RIGHT_PORT
[qemu crash on assert(cleanup_bh)]
The thing is we shouldn't cleanup if it's postcopy resume; the error is set
mostly because the channel is wrong, so we return directly waiting for the user
to retry.
migrate_fd_cleanup() should only be called when migration is cancelled or
completed.
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20210708190653.252961-3-peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
diff --git a/migration/migration.c b/migration/migration.c
index 38ebc6c..20c48cf 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -3979,7 +3979,18 @@
}
if (error_in) {
migrate_fd_error(s, error_in);
- migrate_fd_cleanup(s);
+ if (resume) {
+ /*
+ * Don't do cleanup for resume if channel is invalid, but only dump
+ * the error. We wait for another channel connect from the user.
+ * The error_report still gives HMP user a hint on what failed.
+ * It's normally done in migrate_fd_cleanup(), but call it here
+ * explicitly.
+ */
+ error_report_err(error_copy(s->error));
+ } else {
+ migrate_fd_cleanup(s);
+ }
return;
}
