[I] [BUG] registry/etcdv3: dataListener.interestedURL slice race (no lock) between AddInterestedURL and DataChange [dubbo-go]

["Aias00 (via GitHub)" <gi...@apache.org>]

Aias00 opened a new issue, #3544:
URL: https://github.com/apache/dubbo-go/issues/3544

   ### Problem
   
   `registry/etcdv3.dataListener.interestedURL` is a plain `[]*common.URL` slice with no lock:
   
   ```go
   // registry/etcdv3/listener.go
   type dataListener struct {
       interestedURL []*common.URL
       listener      config_center.ConfigurationListener
   }
   
   func (l *dataListener) AddInterestedURL(url *common.URL) {
       l.interestedURL = append(l.interestedURL, url)   // DoSubscribe path
   }
   
   func (l *dataListener) DataChange(eventType remoting.Event) bool {
       ...
       if slices.ContainsFunc(l.interestedURL, serviceURL.URLEqual) {   // etcd watch goroutine
           l.listener.Process(...)
       }
   }
   ```
   
   `AddInterestedURL` is called from `DoSubscribe` (consumer subscribe path) while `DataChange` runs on the etcd watch goroutine (`ListenServiceEvent`). Concurrent `append` (which may reallocate the slice header) and `slices.ContainsFunc` (which reads the slice header/elements) is a data race. `go test -race` flags it.
   
   ### Current behavior
   
   Two near-simultaneous `DoSubscribe` calls, or a subscribe concurrent with an incoming etcd watch event, race on the `interestedURL` slice header → torn reads, missed event matching, or stale reads dropping events.
   
   ### Expected behavior
   
   `interestedURL` reads and writes must be guarded; `DataChange` must not hold the lock across the external `Process` callback.
   
   ### Suggested approach
   
   - Add a `sync.RWMutex` to `dataListener`.
   - `AddInterestedURL` takes the write lock.
   - `DataChange` does the `slices.ContainsFunc` check under `RLock`, releases it, then dispatches `Process` outside the lock.
   
   ### Acceptance criteria
   
   - [ ] `interestedURL` is accessed under the mutex in both `AddInterestedURL` and `DataChange`.
   - [ ] `DataChange` dispatches `Process` outside the lock.
   - [ ] A concurrency test (concurrent `AddInterestedURL` vs `DataChange`) passes under `-race`.
   


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Re: [I] [BUG] registry/etcdv3: dataListener.interestedURL slice race (no lock) between AddInterestedURL and DataChange [dubbo-go]

["Alanxtl (via GitHub)" <gi...@apache.org>]

Alanxtl closed issue #3544: [BUG] registry/etcdv3: dataListener.interestedURL slice race (no lock) between AddInterestedURL and DataChange
URL: https://github.com/apache/dubbo-go/issues/3544


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Re: [I] [BUG] registry/etcdv3: dataListener.interestedURL slice race (no lock) between AddInterestedURL and DataChange [dubbo-go]

["Alanxtl (via GitHub)" <gi...@apache.org>]

Alanxtl commented on issue #3544:
URL: https://github.com/apache/dubbo-go/issues/3544#issuecomment-5086258170

   not planned


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