[perl #45053] Memory corruption with heavy module loading in threads

In void context, eval leaves garbage on the stack. Don't then
copy this back into the threads->param array!

p4raw-id: //depot/perl@31864

2 files changed, 10 insertions, 2 deletions

diff --git a/ext/threads/t/thread.t b/ext/threads/t/thread.t
index 9a2a097d55..0cc59dc628 100644
--- a/ext/threads/t/thread.t
+++ b/ext/threads/t/thread.t
@@ -30,7 +30,7 @@ BEGIN {
     }
 
     $| = 1;
-    print("1..33\n");   ### Number of tests that will be run ###
+    print("1..34\n");   ### Number of tests that will be run ###
 };
 
 print("ok 1 - Loaded\n");
@@ -194,6 +194,14 @@ fresh_perl_is(<<'EOI', 'ok', { }, 'thread sub via $_[0]');
     print 'ok';
 EOI
 
+# [perl #45053]  Memory corruption from eval return in void context
+fresh_perl_is(<<'EOI', 'ok', { }, 'void eval return');
+    use threads;
+    threads->create(sub { eval '1' });
+    $_->join() for threads->list;
+    print 'ok';
+EOI
+
 # test CLONE_SKIP() functionality
 if ($] >= 5.008007) {
     my %c : shared;
diff --git a/ext/threads/threads.xs b/ext/threads/threads.xs
index e1414de877..54fbaa0e06 100755
--- a/ext/threads/threads.xs
+++ b/ext/threads/threads.xs
@@ -452,7 +452,7 @@ S_ithread_run(void * arg)
         SPAGAIN;
         for (ii=len-1; ii >= 0; ii--) {
             SV *sv = POPs;
-            if (jmp_rc == 0) {
+            if (jmp_rc == 0 && (! (thread->gimme & G_VOID))) {
                 av_store(params, ii, SvREFCNT_inc(sv));
             }
         }