6 files changed, 13 insertions, 4 deletions

diff --git a/mg.c b/mg.c
index dedf381629..7f49f68aa0 100644
--- a/mg.c
+++ b/mg.c
@@ -1723,6 +1723,7 @@ MAGIC *mg;
 	croak("panic: magic_mutexfree");
     MUTEX_DESTROY(MgMUTEXP(mg));
     COND_DESTROY(MgCONDP(mg));
+    SvREFCNT_dec(sv);
     return 0;
 }
 #endif /* USE_THREADS */
diff --git a/op.c b/op.c
index 680b825865..f9449f50d1 100644
--- a/op.c
+++ b/op.c
@@ -1288,7 +1288,7 @@ I32 type;
 
     switch (o->op_type) {
     case OP_ENTERSUB:
-	if ((type == OP_DEFINED) &&
+	if ((type == OP_DEFINED || type == OP_LOCK) &&
 	    !(o->op_flags & OPf_STACKED)) {
 	    o->op_type = OP_RV2CV;             /* entersub => rv2cv */
 	    o->op_ppaddr = ppaddr[OP_RV2CV];
diff --git a/opcode.h b/opcode.h
index 7cf7f66800..1b465ddb30 100644
--- a/opcode.h
+++ b/opcode.h
@@ -2137,7 +2137,7 @@ EXT OP * (*check[]) _((OP *op)) = {
 	ck_null,	/* egrent */
 	ck_null,	/* getlogin */
 	ck_fun,		/* syscall */
-	ck_null,	/* lock */
+	ck_rfun,	/* lock */
 };
 #endif
 
diff --git a/opcode.pl b/opcode.pl
index fb3accc307..f8a7bb7787 100755
--- a/opcode.pl
+++ b/opcode.pl
@@ -654,4 +654,4 @@ getlogin	getlogin		ck_null		st
 syscall		syscall			ck_fun		imst	S L
 
 # For multi-threading
-lock		lock			ck_null		s	S
+lock		lock			ck_rfun		s	S
diff --git a/pp.c b/pp.c
index d002a1f0c5..649506fa89 100644
--- a/pp.c
+++ b/pp.c
@@ -4266,8 +4266,9 @@ void *svv;
 PP(pp_lock)
 {
     dSP;
-#ifdef USE_THREADS
     dTOPss;
+    SV *retsv = sv;
+#ifdef USE_THREADS
     MAGIC *mg;
     
     if (SvROK(sv))
@@ -4284,8 +4285,14 @@ PP(pp_lock)
 	DEBUG_L(PerlIO_printf(PerlIO_stderr(), "0x%lx: pp_lock lock 0x%lx\n",
 			      (unsigned long)thr, (unsigned long)sv);)
 	MUTEX_UNLOCK(MgMUTEXP(mg));
+	SvREFCNT_inc(sv);	/* keep alive until magic_mutexfree */
 	save_destructor(unlock_condpair, sv);
     }
 #endif /* USE_THREADS */
+    if (SvTYPE(retsv) == SVt_PVAV || SvTYPE(retsv) == SVt_PVHV
+	|| SvTYPE(retsv) == SVt_PVCV) {
+	retsv = refto(retsv);
+    }
+    SETs(retsv);
     RETURN;
 }
diff --git a/pp_hot.c b/pp_hot.c
index c19e928f67..bc46cca740 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -1866,6 +1866,7 @@ PP(pp_entersub)
 	    DEBUG_L(PerlIO_printf(PerlIO_stderr(), "%p: pp_entersub lock %p\n",
 				  thr, sv);)
 	    MUTEX_UNLOCK(MgMUTEXP(mg));
+	    SvREFCNT_inc(sv);	/* Keep alive until magic_mutexfree */
 	    save_destructor(unlock_condpair, sv);
 	}
 	MUTEX_LOCK(CvMUTEXP(cv));