conn_delete_all_transactions() should be callable in any context,
resetting ALL transaction related data.
This includes number of active transactions and the transaction
pointer in struct connection.
So reset conn->trans to NULL in conn_delete_all_transactions() and
do the cleanup for each transaction in destroy_transaction().
This avoids triggering the assert() in conn_delete_all_transactions()
in case e.g. ignore_connection() was called while an operation inside
a transaction was performed, or XS_RESET_WATCHES was called in a
transaction.
This is XSA-484 / CVE-2026-23557.
Reported-by: Andrii Sultanov <andriy.sultanov@vates.tech>
Fixes: 1f9d04fb02 ("xenstored: allow guest to shutdown all its watches/transactions")
Signed-off-by: Juergen Gross <jgross@suse.com>