# panic: sync: RUnlock of unlocked RWMutex

- **ID:** `go/rwmutex-read-lock-recursive`
- **Domain:** go
- **Category:** runtime_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

Calling RUnlock without a matching RLock, often due to recursive read locking.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 1.19 | active | — | — |

## Workarounds

1. **** (99% success)
   ```
   mu.RLock(); defer mu.RUnlock()
   ```
2. **** (95% success)
   ```
   Restructure code to hold lock only once per goroutine.
   ```

## Dead Ends

- **** — RLock is not reentrant; multiple RLock without unlock causes deadlock or panic. (85% fail)
- **** — Attempting to upgrade read lock to write lock causes deadlock. (90% fail)