From: Nicholas Clark <nick@ccl4.org>
Date: Sun, 1 May 2011 21:02:59 +0000 (+0100)
Subject: Skip GvFILE on ithreaded 5.8.8 and earlier, as it can point to freed memory.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=2b217e71c876fadb2ec3cbbdef749786610564e8;hp=5f03b77e418d07ecc0a99453ba27df9be95ee32d;p=p5sagit%2FDevel-Size.git

Skip GvFILE on ithreaded 5.8.8 and earlier, as it can point to freed memory.

Probably better to slightly under report sizes, than report something random or
SEGV.
---

diff --git a/Size.xs b/Size.xs
index 1911d2e..a3f6eed 100644
--- a/Size.xs
+++ b/Size.xs
@@ -667,8 +667,16 @@ sv_size(pTHX_ struct state *const st, const SV * const orig_thing,
     if(isGV_with_GP(thing)) {
 	st->total_size += GvNAMELEN(thing);
 #ifdef GvFILE
-	/* Is there a file? */
+#  if !defined(USE_ITHREADS) || (PERL_VERSION > 8 || (PERL_VERSION == 8 && PERL_SUBVERSION > 8))
+	/* With itreads, before 5.8.9, this can end up pointing to freed memory
+	   if the GV was created in an eval, as GvFILE() points to CopFILE(),
+	   and the relevant COP has been freed on scope cleanup after the eval.
+	   5.8.9 adds a binary compatible fudge that catches the vast majority
+	   of cases. 5.9.something added a proper fix, by converting the GP to
+	   use a shared hash key (porperly reference counted), instead of a
+	   char * (owned by who knows? possibly no-one now) */
 	check_new_and_strlen(st, GvFILE(thing));
+#  endif
 #endif
 	/* Is there something hanging off the glob? */
 	if (check_new(st, GvGP(thing))) {