1 files changed, 5 insertions, 1 deletions
diff --git a/sv.c b/sv.c
index a091bf00d0..a42452aa14 100644
--- a/sv.c
+++ b/sv.c
@@ -4033,7 +4033,11 @@ Perl_sv_setsv_flags(pTHX_ SV *dstr, register SV* sstr, const I32 flags)
 		if (len > 1 && name[len-2] == ':' && name[len-1] == ':') {
 		    /* Set aside the old stash, so we can reset isa caches
 		       on its subclasses. */
-		    old_stash = GvHV(dstr);
+		    if((old_stash = GvHV(dstr)));
+			/* Make sure we do not lose it early. */
+			SvREFCNT_inc_simple_void_NN(
+			 sv_2mortal((SV *)old_stash)
+			);
 		    reset_isa = TRUE;
 		}