prohibit thread join()ing itself (from Dan Sugalski)

p4raw-id: //depot/perl@3645

diff --git a/ext/Thread/Thread.xs b/ext/Thread/Thread.xs
index f8b544d..5d61941 100644 (file)
--- 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);