The real fix must be more involved. The line of code all the leaky
call stacks seem to go through is op.c:2949, the PmopSTASH_set()
line of Perl_newPMOP().
p4raw-id: //depot/perl@11099
#ifdef USE_ITHREADS
# define PmopSTASHPV(o) ((o)->op_pmstashpv)
-# define PmopSTASHPV_set(o,pv) (Safefree((o)->op_pmstashpv), (o)->op_pmstashpv = ((pv) ? savepv(pv) : Nullch))
+# define PmopSTASHPV_set(o,pv) ((o)->op_pmstashpv = ((pv) ? savepv(pv) : Nullch))
# define PmopSTASH(o) (PmopSTASHPV(o) \
? gv_stashpv(PmopSTASHPV(o),GV_ADD) : Nullhv)
# define PmopSTASH_set(o,hv) PmopSTASHPV_set(o, (hv) ? HvNAME(hv) : Nullch)