From: Ilya Zakharevich <ilya@math.ohio-state.edu>
Date: Tue, 7 Jan 1997 12:56:02 +0000 (-0500)
Subject: Patch for Object subroutines
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=174150afa5efdafc0e94a18211d3c9aa06b15cd9;p=p5sagit%2Fp5-mst-13.2.git

Patch for Object subroutines

The following script segfaults with _17 ():

#!./perl
my $x;

BEGIN {
  $x = sub {print "in sub.\n"; undef $x};
  sub X::DESTROY { print "Destroying.\n"}
  bless $x, 'X';
}

# At this moment refcount of $x and &$x are 1 (we need a closure for this
# because of a sub leak).

&$x();
print "x: `$x'.\n";
---

diff --git a/cop.h b/cop.h
index 543c039..20301ff 100644
--- a/cop.h
+++ b/cop.h
@@ -46,6 +46,8 @@ struct block_sub {
 	cx->blk_sub.dfoutgv = defoutgv;					\
 	(void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
 
+/* We muck with cxstack_ix since _dec may call a DESTROY, overwriting cx. */
+
 #define POPSUB(cx)							\
 	if (cx->blk_sub.hasargs) {   /* put back old @_ */		\
 	    GvAV(defgv) = cx->blk_sub.savearray;			\
@@ -55,7 +57,9 @@ struct block_sub {
 	        if (cx->blk_sub.hasargs) {				\
 	    	    SvREFCNT_inc((SV*)cx->blk_sub.argarray);		\
 		}							\
+		cxstack_ix++;						\
 		SvREFCNT_dec((SV*)cx->blk_sub.cv);			\
+		cxstack_ix--;						\
 	    }								\
 	}