1 files changed, 2 insertions, 0 deletions
diff --git a/ext/Thread/Thread.xs b/ext/Thread/Thread.xs
index f8b544da91..5d61941241 100644
--- a/ext/Thread/Thread.xs
+++ b/ext/Thread/Thread.xs
@@ -353,6 +353,8 @@ join(t)
 	int	i = NO_INIT
     PPCODE:
 #ifdef USE_THREADS
+	if (t == thr)
+	    croak("Attempt to join self");
 	DEBUG_S(PerlIO_printf(PerlIO_stderr(), "%p: joining %p (state %u)\n",
 			      thr, t, ThrSTATE(t)););
     	MUTEX_LOCK(&t->mutex);