diff --git a/js/src/jsapi.c b/js/src/jsapi.c
index 8771046c258..628180c86b8 100644
--- a/js/src/jsapi.c
+++ b/js/src/jsapi.c
@@ -1608,18 +1608,30 @@ JS_LockGCThing(JSContext *cx, void *thing)
     return ok;
 }
 
+JS_PUBLIC_API(JSBool)
+JS_LockGCThingRT(JSRuntime *rt, void *thing)
+{
+    return js_LockGCThingRT(rt, thing);
+}
+
 JS_PUBLIC_API(JSBool)
 JS_UnlockGCThing(JSContext *cx, void *thing)
 {
     JSBool ok;
 
     CHECK_REQUEST(cx);
-    ok = js_UnlockGCThing(cx, thing);
+    ok = js_UnlockGCThingRT(cx->runtime, thing);
     if (!ok)
         JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_CANT_UNLOCK);
     return ok;
 }
 
+JS_PUBLIC_API(JSBool)
+JS_UnlockGCThingRT(JSRuntime *rt, void *thing)
+{
+    return js_UnlockGCThingRT(rt, thing);
+}
+
 JS_PUBLIC_API(void)
 JS_MarkGCThing(JSContext *cx, void *thing, const char *name, void *arg)
 {
diff --git a/js/src/jsapi.h b/js/src/jsapi.h
index 143ec37c156..01a49e6e8ce 100644
--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -592,9 +592,15 @@ JS_MapGCRoots(JSRuntime *rt, JSGCRootMapFun map, void *data);
 extern JS_PUBLIC_API(JSBool)
 JS_LockGCThing(JSContext *cx, void *thing);
 
+extern JS_PUBLIC_API(JSBool)
+JS_LockGCThingRT(JSRuntime *rt, void *thing);
+
 extern JS_PUBLIC_API(JSBool)
 JS_UnlockGCThing(JSContext *cx, void *thing);
 
+extern JS_PUBLIC_API(JSBool)
+JS_UnlockGCThingRT(JSRuntime *rt, void *thing);
+
 /*
  * For implementors of JSObjectOps.mark, to mark a GC-thing reachable via a
  * property or other strong ref identified for debugging purposes by name.
diff --git a/js/src/jsgc.c b/js/src/jsgc.c
index e29737bcf31..87cf685cfed 100644
--- a/js/src/jsgc.c
+++ b/js/src/jsgc.c
@@ -543,7 +543,15 @@ retry:
 JSBool
 js_LockGCThing(JSContext *cx, void *thing)
 {
-    JSRuntime *rt;
+    JSBool ok = js_LockGCThingRT(cx->runtime, thing);
+    if (!ok)
+        JS_ReportOutOfMemory(cx);
+    return ok;
+}
+
+JSBool
+js_LockGCThingRT(JSRuntime *rt, void *thing)
+{
     uint8 *flagp, flags, lockbits;
     JSBool ok;
     JSGCLockHashEntry *lhe;
@@ -553,8 +561,7 @@ js_LockGCThing(JSContext *cx, void *thing)
     flagp = js_GetGCThingFlags(thing);
     flags = *flagp;
 
-    ok = JS_TRUE;
-    rt = cx->runtime;
+    ok = JS_FALSE;
     JS_LOCK_GC(rt);
     lockbits = (flags & GCF_LOCKMASK);
 
@@ -568,7 +575,7 @@ js_LockGCThing(JSContext *cx, void *thing)
                                          sizeof(JSGCLockHashEntry),
                                          GC_ROOTS_SIZE);
                     if (!rt->gcLocksHash)
-                        goto outofmem;
+                        goto error;
                 } else {
 #ifdef DEBUG
                     JSDHashEntryHdr *hdr = 
@@ -580,7 +587,7 @@ js_LockGCThing(JSContext *cx, void *thing)
                 lhe = (JSGCLockHashEntry *)
                     JS_DHashTableOperate(rt->gcLocksHash, thing, JS_DHASH_ADD);
                 if (!lhe)
-                    goto outofmem;
+                    goto error;
                 lhe->thing = thing;
                 lhe->count = 1;
                 *flagp = (uint8)(flags + GCF_LOCK);
@@ -603,20 +610,15 @@ js_LockGCThing(JSContext *cx, void *thing)
     }
 
     METER(rt->gcStats.lock++);
-out:
+    ok = JS_TRUE;
+error:
     JS_UNLOCK_GC(rt);
     return ok;
-
-outofmem:
-    JS_ReportOutOfMemory(cx);
-    ok = JS_FALSE;
-    goto out;
 }
 
 JSBool
-js_UnlockGCThing(JSContext *cx, void *thing)
+js_UnlockGCThingRT(JSRuntime *rt, void *thing)
 {
-    JSRuntime *rt;
     uint8 *flagp, flags, lockbits;
     JSGCLockHashEntry *lhe;
 
@@ -625,7 +627,6 @@ js_UnlockGCThing(JSContext *cx, void *thing)
     flagp = js_GetGCThingFlags(thing);
     flags = *flagp;
 
-    rt = cx->runtime;
     JS_LOCK_GC(rt);
     lockbits = (flags & GCF_LOCKMASK);
 
diff --git a/js/src/jsgc.h b/js/src/jsgc.h
index 5d219ba2b62..4aa16c1682a 100644
--- a/js/src/jsgc.h
+++ b/js/src/jsgc.h
@@ -121,7 +121,10 @@ extern JSBool
 js_LockGCThing(JSContext *cx, void *thing);
 
 extern JSBool
-js_UnlockGCThing(JSContext *cx, void *thing);
+js_LockGCThingRT(JSRuntime *rt, void *thing);
+
+extern JSBool
+js_UnlockGCThingRT(JSRuntime *rt, void *thing);
 
 extern JSBool 
 js_IsAboutToBeFinalized(JSContext *cx, void *thing);
diff --git a/js/src/jsnum.c b/js/src/jsnum.c
index 9ab81658e5a..32e35989897 100644
--- a/js/src/jsnum.c
+++ b/js/src/jsnum.c
@@ -500,9 +500,9 @@ js_FinishRuntimeNumberState(JSContext *cx)
 {
     JSRuntime *rt = cx->runtime;
 
-    js_UnlockGCThing(cx, rt->jsNaN);
-    js_UnlockGCThing(cx, rt->jsNegativeInfinity);
-    js_UnlockGCThing(cx, rt->jsPositiveInfinity);
+    js_UnlockGCThingRT(rt, rt->jsNaN);
+    js_UnlockGCThingRT(rt, rt->jsNegativeInfinity);
+    js_UnlockGCThingRT(rt, rt->jsPositiveInfinity);
 
     rt->jsNaN = NULL;
     rt->jsNegativeInfinity = NULL;
diff --git a/js/src/jsstr.c b/js/src/jsstr.c
index 58f4e659534..1c4f9102680 100644
--- a/js/src/jsstr.c
+++ b/js/src/jsstr.c
@@ -2316,7 +2316,7 @@ js_FinishRuntimeStringState(JSContext *cx)
 {
     JSRuntime *rt = cx->runtime;
 
-    js_UnlockGCThing(cx, rt->emptyString);
+    js_UnlockGCThingRT(rt, rt->emptyString);
     rt->emptyString = NULL;
 }