diff --git a/test/lib/envutil.rb b/test/lib/envutil.rb
index 5d3bce99ec..f4d63d5a0a 100644
--- a/test/lib/envutil.rb
+++ b/test/lib/envutil.rb
@@ -65,6 +65,41 @@ module EnvUtil
   end
   module_function :apply_timeout_scale
 
+  def terminate(pid, signal = :TERM, pgroup = nil, reprieve = 1)
+    reprieve = apply_timeout_scale(reprieve) if reprieve
+
+    signals = Array(signal).select do |sig|
+      DEFAULT_SIGNALS[sig.to_s] or
+        DEFAULT_SIGNALS[Signal.signame(sig)] rescue false
+    end
+    signals |= [:ABRT, :KILL]
+    case pgroup
+    when 0, true
+      pgroup = -pid
+    when nil, false
+      pgroup = pid
+    end
+    while signal = signals.shift
+      begin
+        Process.kill signal, pgroup
+      rescue Errno::EINVAL
+        next
+      rescue Errno::ESRCH
+        break
+      end
+      if signals.empty? or !reprieve
+        Process.wait(pid)
+      else
+        begin
+          Timeout.timeout(reprieve) {Process.wait(pid)}
+        rescue Timeout::Error
+        end
+      end
+    end
+    $?
+  end
+  module_function :terminate
+
   def invoke_ruby(args, stdin_data = "", capture_stdout = false, capture_stderr = false,
                   encoding: nil, timeout: 10, reprieve: 1, timeout_error: Timeout::Error,
                   stdout_filter: nil, stderr_filter: nil,
@@ -72,7 +107,6 @@ module EnvUtil
                   rubybin: EnvUtil.rubybin, precommand: nil,
                   **opt)
     timeout = apply_timeout_scale(timeout)
-    reprieve = apply_timeout_scale(reprieve) if reprieve
 
     in_c, in_p = IO.pipe
     out_p, out_c = IO.pipe if capture_stdout
@@ -108,35 +142,7 @@ module EnvUtil
       if (!th_stdout || th_stdout.join(timeout)) && (!th_stderr || th_stderr.join(timeout))
         timeout_error = nil
       else
-        signals = Array(signal).select do |sig|
-          DEFAULT_SIGNALS[sig.to_s] or
-            DEFAULT_SIGNALS[Signal.signame(sig)] rescue false
-        end
-        signals |= [:ABRT, :KILL]
-        case pgroup = opt[:pgroup]
-        when 0, true
-          pgroup = -pid
-        when nil, false
-          pgroup = pid
-        end
-        while signal = signals.shift
-          begin
-            Process.kill signal, pgroup
-          rescue Errno::EINVAL
-            next
-          rescue Errno::ESRCH
-            break
-          end
-          if signals.empty? or !reprieve
-            Process.wait(pid)
-          else
-            begin
-              Timeout.timeout(reprieve) {Process.wait(pid)}
-            rescue Timeout::Error
-            end
-          end
-        end
-        status = $?
+        status = terminate(pid, signal, opt[:pgroup], reprieve)
       end
       stdout = th_stdout.value if capture_stdout
       stderr = th_stderr.value if capture_stderr && capture_stderr != :merge_to_stdout
diff --git a/test/ruby/test_thread.rb b/test/ruby/test_thread.rb
index 51c0338595..f133126934 100644
--- a/test/ruby/test_thread.rb
+++ b/test/ruby/test_thread.rb
@@ -967,7 +967,12 @@ _eom
       pid = cpid
       t0 = Time.now.to_f
       Process.kill(:SIGINT, pid)
-      Timeout.timeout(10) { Process.wait(pid) }
+      begin
+        Timeout.timeout(10) { Process.wait(pid) }
+      rescue Timeout::Error
+        EnvUtil.terminate(pid)
+        raise
+      end
       t1 = Time.now.to_f
       [$?, t1 - t0, err_p.read]
     end