diff --git a/repos/ports/src/app/gdb_monitor/cpu_session_component.cc b/repos/ports/src/app/gdb_monitor/cpu_session_component.cc
index 5c3d2edb32..711a98794a 100644
--- a/repos/ports/src/app/gdb_monitor/cpu_session_component.cc
+++ b/repos/ports/src/app/gdb_monitor/cpu_session_component.cc
@@ -267,7 +267,8 @@ void Cpu_session_component::kill_thread(Thread_capability thread_cap)
 	Cpu_thread_component *cpu_thread = lookup_cpu_thread(thread_cap);
 
 	if (cpu_thread) {
-		genode_remove_thread(cpu_thread->lwpid());
+		if (cpu_thread->lwpid())
+			genode_remove_thread(cpu_thread->lwpid());
 		_thread_list.remove(cpu_thread);
 		destroy(_md_alloc, cpu_thread);
 	} else
diff --git a/repos/ports/src/app/gdb_monitor/cpu_thread_component.h b/repos/ports/src/app/gdb_monitor/cpu_thread_component.h
index ce5f1b1dd6..af994e964a 100644
--- a/repos/ports/src/app/gdb_monitor/cpu_thread_component.h
+++ b/repos/ports/src/app/gdb_monitor/cpu_thread_component.h
@@ -36,8 +36,8 @@ class Gdb_monitor::Cpu_thread_component : public Rpc_object<Cpu_thread>,
 
 		Cpu_session_component &_cpu_session_component;
 		Cpu_thread_client      _parent_cpu_thread;
-		unsigned long          _lwpid;
-		addr_t                 _initial_ip;
+		unsigned long          _lwpid { 0 };
+		addr_t                 _initial_ip { 0 };
 
 		/*
 		 * SIGTRAP, SIGSTOP and SIGINT must get delivered to the gdbserver code