diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index 3a98cad..06c3a42 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -22,6 +22,7 @@
 #include <thread>
 #include <vector>
 
+#include <android-base/scopeguard.h>
 #include <binder/Parcel.h>
 #include <binder/RpcServer.h>
 #include <log/log.h>
@@ -32,6 +33,7 @@
 
 namespace android {
 
+using base::ScopeGuard;
 using base::unique_fd;
 
 RpcServer::RpcServer() {}
@@ -157,10 +159,11 @@
 
     // TODO(b/183988761): cannot trust this simple ID
     LOG_ALWAYS_FATAL_IF(!mAgreedExperimental, "no!");
+    bool idValid = true;
     int32_t id;
     if (sizeof(id) != read(clientFd.get(), &id, sizeof(id))) {
         ALOGE("Could not read ID from fd %d", clientFd.get());
-        return;
+        idValid = false;
     }
 
     std::thread thisThread;
@@ -172,8 +175,13 @@
         LOG_ALWAYS_FATAL_IF(threadId == mConnectingThreads.end(),
                             "Must establish connection on owned thread");
         thisThread = std::move(threadId->second);
+        ScopeGuard detachGuard = [&]() { thisThread.detach(); };
         mConnectingThreads.erase(threadId);
 
+        if (!idValid) {
+            return;
+        }
+
         if (id == RPC_SESSION_ID_NEW) {
             LOG_ALWAYS_FATAL_IF(mSessionIdCounter >= INT32_MAX, "Out of session IDs");
             mSessionIdCounter++;
@@ -190,6 +198,9 @@
             }
             session = it->second;
         }
+
+        detachGuard.Disable();
+        session->preJoin(std::move(thisThread));
     }
 
     // avoid strong cycle
@@ -199,7 +210,7 @@
     // DO NOT ACCESS MEMBER VARIABLES BELOW
     //
 
-    session->join(std::move(thisThread), std::move(clientFd));
+    session->join(std::move(clientFd));
 }
 
 bool RpcServer::setupSocketServer(const RpcSocketAddress& addr) {
diff --git a/libs/binder/RpcSession.cpp b/libs/binder/RpcSession.cpp
index f32aa7a..05fa49e 100644
--- a/libs/binder/RpcSession.cpp
+++ b/libs/binder/RpcSession.cpp
@@ -131,14 +131,16 @@
     return OK;
 }
 
-void RpcSession::join(std::thread thread, unique_fd client) {
+void RpcSession::preJoin(std::thread thread) {
     LOG_ALWAYS_FATAL_IF(thread.get_id() != std::this_thread::get_id(), "Must own this thread");
 
     {
         std::lock_guard<std::mutex> _l(mMutex);
         mThreads[thread.get_id()] = std::move(thread);
     }
+}
 
+void RpcSession::join(unique_fd client) {
     // must be registered to allow arbitrary client code executing commands to
     // be able to do nested calls (we can't only read from it)
     sp<RpcConnection> connection = assignServerToThisThread(std::move(client));
diff --git a/libs/binder/include/binder/RpcSession.h b/libs/binder/include/binder/RpcSession.h
index 92ee100..bcc213c 100644
--- a/libs/binder/include/binder/RpcSession.h
+++ b/libs/binder/include/binder/RpcSession.h
@@ -114,7 +114,10 @@
 
     status_t readId();
 
-    void join(std::thread thread, base::unique_fd client);
+    // transfer ownership of thread
+    void preJoin(std::thread thread);
+    // join on thread passed to preJoin
+    void join(base::unique_fd client);
     void terminateLocked();
 
     struct RpcConnection : public RefBase {