Can't get #17492 to work with -Uuseperlio otherwise (either

[p5sagit/p5-mst-13.2.git] / scope.c

diff --git a/scope.c b/scope.c
index a1fdfd1..673b64c 100644 (file)
--- a/scope.c
+++ b/scope.c
@@ -81,14 +81,21 @@ Perl_new_stackinfo(pTHX_ I32 stitems, I32 cxitems)
     si->si_cxix = -1;
     si->si_type = PERLSI_UNDEF;
     New(56, si->si_cxstack, cxitems, PERL_CONTEXT);
+    /* Without any kind of initialising PUSHSUBST()
+     * in pp_subst() will read uninitialised heap. */
+    Poison(si->si_cxstack, cxitems, PERL_CONTEXT);
     return si;
 }
 
 I32
 Perl_cxinc(pTHX)
 {
+    IV old_max = cxstack_max;
     cxstack_max = GROW(cxstack_max);
     Renew(cxstack, cxstack_max + 1, PERL_CONTEXT);     /* XXX should fix CXINC macro */
+    /* Without any kind of initialising deep enough recursion
+     * will end up reading uninitialised PERL_CONTEXTs. */
+    Poison(cxstack + old_max + 1, cxstack_max - old_max, PERL_CONTEXT);
     return cxstack_ix + 1;
 }