Maintenance: prevent exit race condition for loops

internal/dns/loop.go

@@ -159,6 +159,11 @@ func (l *looper) Run(ctx context.Context, done chan<- struct{}) {
 				stayHere = false
 			case err := <-waitError: // unexpected error
 				unboundCancel()
+				if ctx.Err() != nil {
+					close(waitError)
+					closeStreams()
+					return
+				}
 				l.state.setStatusWithLock(constants.Crashed)
 				const fallback = true
 				l.useUnencryptedDNS(fallback)

internal/openvpn/loop.go

@@ -211,6 +211,14 @@ func (l *looper) Run(ctx context.Context, done chan<- struct{}) { //nolint:gocog
 				stayHere = false
 			case err := <-waitError: // unexpected error
 				openvpnCancel()
+				if ctx.Err() != nil {
+					close(waitError)
+					close(stdoutLines)
+					close(stderrLines)
+					<-lineCollectionDone
+					<-portForwardDone
+					return
+				}
 				l.state.setStatusWithLock(constants.Crashed)
 				l.logAndWait(ctx, err)
 				l.crashed = true

internal/shadowsocks/loop.go

@@ -139,6 +139,9 @@ func (l *looper) Run(ctx context.Context, done chan<- struct{}) {
 			case err := <-waitError: // unexpected error
 				shadowsocksCancel()
 				close(waitError)
+				if ctx.Err() != nil {
+					return
+				}
 				l.state.setStatusWithLock(constants.Crashed)
 				l.logAndWait(ctx, err)
 				crashed = true