Calling transaction_start() through Samba's smbconf Python bindings with a CTDB backed registry emits:

"no talloc stackframe at ../../source3/lib/g_lock.c:1210, leaking memory"

Here's a minimal reproducer, with CTDB running (and healthy):
```python
from samba.samba3 import param, smbconf

param.get_context().load("/usr/local/etc/samba/smb.conf")
conf = smbconf.init_reg(None)
print("before transaction_start()")
conf.transaction_start()
print("after transaction_start()")
conf.transaction_cancel()
```

which displays:
before transaction_start()
no talloc stackframe at ../../source3/lib/g_lock.c:1210, leaking memory
after transaction_start()

Configuration loading and registry initialization succeed. The warning occurs during transaction_start(). The execution continues, but there's a smb_panic("No talloc stackframe") for this condition under developer builds.

The equivalent net conf import operation succeeds without the warning.