embed: fix nil pointer dereference when stopServer

Since v3.4.25, ETCD server introduces http-only urls flag to expose gRPC-only endpoints. When user enables this feature, the stopServer will panic during terminating. If the server is leader, it won't have chance to transfer the leadership. ``` Jul 07 14:43:04 etcd[11502]: received terminated signal, shutting down... Jul 07 14:43:04 etcd[11502]: WARNING: 2023/07/07 14:43:04 grpc: addrConn.createTransport failed to connect to {0.0.0.0:2379 <nil> 0 <nil>}. Err :connection error: desc = "transport: Error while dialing dial tcp 0.0.0.0:2379: connect: connection refused". Reconnecting...Jul 07 14:43:04 etcd[11502]: WARNING: 2023/07/07 14:43:04 grpc: addrConn.createTransport failed to connect to {0.0.0.0:2379 <nil> 0 <nil>}. Err :connection error: desc = "transport: Error while dialing dial tcp 0.0.0.0:2379: connect: connection refused". Reconnecting... Jul 07 14:43:04 etcd[11502]: panic: runtime error: invalid memory address or nil pointer dereference Jul 07 14:43:04 etcd[11502]: [signal SIGSEGV: segmentation violation code=0x1 addr=0x130 pc=0x9ccd45] Jul 07 14:43:04 etcd[11502]: goroutine 225 [running]: Jul 07 14:43:04 etcd[11502]: google.golang.org/grpc.(*Server).Stop(0x0) Jul 07 14:43:04 etcd[11502]: /home/fuwei/go/pkg/mod/google.golang.org/[email protected]/server.go:1390 +0x45 Jul 07 14:43:04 etcd[11502]: go.etcd.io/etcd/embed.stopServers.func1() Jul 07 14:43:04 etcd[11502]: /home/fuwei/go/src/go.etcd.io/etcd/embed/etcd.go:431 +0x3c Jul 07 14:43:04 etcd[11502]: go.etcd.io/etcd/embed.stopServers({0x115a558, 0xc000278b70}, 0xc00024f248) Jul 07 14:43:04 etcd[11502]: /home/fuwei/go/src/go.etcd.io/etcd/embed/etcd.go:438 +0x7d Jul 07 14:43:04 etcd[11502]: go.etcd.io/etcd/embed.(*Etcd).Close(0xc0004d6600) Jul 07 14:43:04 etcd[11502]: /home/fuwei/go/src/go.etcd.io/etcd/embed/etcd.go:392 +0x835 Jul 07 14:43:04 etcd[11502]: go.etcd.io/etcd/pkg/osutil.HandleInterrupts.func1() Jul 07 14:43:04 etcd[11502]: /home/fuwei/go/src/go.etcd.io/etcd/pkg/osutil/interrupt_unix.go:70 +0x284 Jul 07 14:43:04 etcd[11502]: created by go.etcd.io/etcd/pkg/osutil.HandleInterrupts Jul 07 14:43:04 etcd[11502]: /home/fuwei/go/src/go.etcd.io/etcd/pkg/osutil/interrupt_unix.go:53 +0xce Jul 07 14:43:04 systemd[1]: etcd.service: Main process exited, code=exited, status=2/INVALIDARGUMENT ``` Signed-off-by: Wei Fu <[email protected]>
etcd-io · Jul 7, 2023 · 66713f6 · 66713f6
1 parent fee612d
commit 66713f6
Showing 1 changed file with 8 additions and 6 deletions.
diff --git a/embed/etcd.go b/embed/etcd.go
@@ -424,18 +424,20 @@ func (e *Etcd) Close() {
 }
 
 func stopServers(ctx context.Context, ss *servers) {
-	shutdownNow := func() {
-		// first, close the http.Server
+	// first, close the http.Server
+	if ss.http != nil {
 		ss.http.Shutdown(ctx)
-		// then close grpc.Server; cancels all active RPCs
-		ss.grpc.Stop()
+	}
+
+	if ss.grpc == nil {
+		return
 	}
 
 	// do not grpc.Server.GracefulStop with TLS enabled etcd server
 	// See https://github.com/grpc/grpc-go/issues/1384#issuecomment-317124531
 	// and https://github.com/etcd-io/etcd/issues/8916
 	if ss.secure && ss.http != nil {
-		shutdownNow()
+		ss.grpc.Stop()
 		return
 	}
 
@@ -453,7 +455,7 @@ func stopServers(ctx context.Context, ss *servers) {
 	case <-ctx.Done():
 		// took too long, manually close open transports
 		// e.g. watch streams
-		shutdownNow()
+		ss.grpc.Stop()
 
 		// concurrent GracefulStop should be interrupted
 		<-ch