All the bits of clone_params.flags need to be initialised, not just

CLONEf_JOIN_IN.

p4raw-id: //depot/perl@27169

diff --git a/ext/threads/threads.xs b/ext/threads/threads.xs
index f0d9d32..38c5666 100755 (executable)
--- a/ext/threads/threads.xs
+++ b/ext/threads/threads.xs
@@ -629,7 +629,7 @@ Perl_ithread_join(pTHX_ SV *obj)
          PerlInterpreter *other_perl = thread->interp;
          CLONE_PARAMS clone_params;
          clone_params.stashes = newAV();
-         clone_params.flags |= CLONEf_JOIN_IN;
+         clone_params.flags = CLONEf_JOIN_IN;
          PL_ptr_table = ptr_table_new();
          current_thread = Perl_ithread_get(aTHX);
          Perl_ithread_set(aTHX_ thread);