It's really hard to debug deadlock problems without accessing user's codebase, trace can only help spot the nearest code but would not be enough for spot specific code.
there're some ways to improve it

• use parking_lot'sdeadlock detect feature which requires we replace all lock with parking_lot(it seems possible cause most lock we're using are tokio's lock and it supportsparking_lot feature)
• compiler instruments: which is more flexible but needs to instrument every lock operation and hard to be shipped in production release