The route socket and its storage was detached while still reading [v9_18]
The interfacemgr and the .route was being detached while the network manager had pending read from the socket. Instead of detaching from the socket, we need to cancel the read which in turn will detach the route socket and the associated interfacemgr.
Backport of !6169 (merged)
Edited by Ondřej Surý