Potential deadlock when starting the encryption thread #8402
Description
Inside the encryption thread, before creating an internal connection, the non-recursive mutex Jrd::Database::dbb_thread_mutex is locked. This can lead to a deadlock if an exception is thrown during the connection process and the release_attachment function is called, as it also attempts to lock this mutex.
This issue affects all major versions: 3, 4, 5, and 6. A PR with the fix will be provided shortly.