diff --git a/js/src/jslock.cpp b/js/src/jslock.cpp
index 867d0bdecd0..0297a626581 100644
--- a/js/src/jslock.cpp
+++ b/js/src/jslock.cpp
@@ -303,7 +303,7 @@ js_FinishLock(JSThinLock *tl)
 #include <stdio.h>
 #include "jsdhash.h"
 
-static FILE *logfp;
+static FILE *logfp = NULL;
 static JSDHashTable logtbl;
 
 typedef struct logentry {
@@ -314,7 +314,7 @@ typedef struct logentry {
 } logentry;
 
 static void
-logit(JSScope *scope, char op, const char *file, int line)
+logit(JSTitle *title, char op, const char *file, int line)
 {
     logentry *entry;
 
@@ -324,35 +324,35 @@ logit(JSScope *scope, char op, const char *file, int line)
             return;
         setvbuf(logfp, NULL, _IONBF, 0);
     }
-    fprintf(logfp, "%p %c %s %d\n", scope, op, file, line);
+    fprintf(logfp, "%p %d %c %s %d\n", title, title->u.count, op, file, line);
 
     if (!logtbl.entryStore &&
         !JS_DHashTableInit(&logtbl, JS_DHashGetStubOps(), NULL,
                            sizeof(logentry), 100)) {
         return;
     }
-    entry = (logentry *) JS_DHashTableOperate(&logtbl, scope, JS_DHASH_ADD);
+    entry = (logentry *) JS_DHashTableOperate(&logtbl, title, JS_DHASH_ADD);
     if (!entry)
         return;
-    entry->stub.key = scope;
+    entry->stub.key = title;
     entry->op = op;
     entry->file = file;
     entry->line = line;
 }
 
 void
-js_unlog_scope(JSScope *scope)
+js_unlog_title(JSTitle *title)
 {
     if (!logtbl.entryStore)
         return;
-    (void) JS_DHashTableOperate(&logtbl, scope, JS_DHASH_REMOVE);
+    (void) JS_DHashTableOperate(&logtbl, title, JS_DHASH_REMOVE);
 }
 
-# define LOGIT(scope,op) logit(scope, op, __FILE__, __LINE__)
+# define LOGIT(title,op) logit(title, op, __FILE__, __LINE__)
 
 #else
 
-# define LOGIT(scope,op) /* nothing */
+# define LOGIT(title, op) /* nothing */
 
 #endif /* DEBUG_SCOPE_COUNT */
 
@@ -665,7 +665,7 @@ js_GetSlotThreadSafe(JSContext *cx, JSObject *obj, uint32 slot)
             if (!NativeCompareAndSwap(&tl->owner, me, 0)) {
                 /* Assert that scope locks never revert to flyweight. */
                 JS_ASSERT(title->ownercx != cx);
-                LOGIT(scope, '1');
+                LOGIT(title, '1');
                 title->u.count = 1;
                 js_UnlockObj(cx, obj);
             }
@@ -755,7 +755,7 @@ js_SetSlotThreadSafe(JSContext *cx, JSObject *obj, uint32 slot, jsval v)
             if (!NativeCompareAndSwap(&tl->owner, me, 0)) {
                 /* Assert that scope locks never revert to flyweight. */
                 JS_ASSERT(title->ownercx != cx);
-                LOGIT(scope, '1');
+                LOGIT(title, '1');
                 title->u.count = 1;
                 js_UnlockObj(cx, obj);
             }
@@ -1211,7 +1211,7 @@ js_UnlockTitle(JSContext *cx, JSTitle *title)
         JS_ASSERT(0);   /* unbalanced unlock */
         return;
     }
-    LOGIT(scope, '-');
+    LOGIT(title, '-');
     if (--title->u.count == 0)
         ThinUnlock(&title->lock, me);
 }
@@ -1279,7 +1279,7 @@ js_TransferTitle(JSContext *cx, JSTitle *oldtitle, JSTitle *newtitle)
     /*
      * Reset oldtitle's lock state so that it is completely unlocked.
      */
-    LOGIT(oldscope, '0');
+    LOGIT(oldtitle, '0');
     oldtitle->u.count = 0;
     ThinUnlock(&oldtitle->lock, CX_THINLOCK_ID(cx));
 }
@@ -1350,6 +1350,10 @@ js_InitTitle(JSContext *cx, JSTitle *title)
 void
 js_FinishTitle(JSContext *cx, JSTitle *title)
 {
+#ifdef DEBUG_SCOPE_COUNT
+    js_unlog_title(title);
+#endif
+
 #ifdef JS_THREADSAFE
     /* Title must be single-threaded at this point, so set ownercx. */
     JS_ASSERT(title->u.count == 0);
diff --git a/js/src/jsscope.cpp b/js/src/jsscope.cpp
index c6a13450f74..941733062f3 100644
--- a/js/src/jsscope.cpp
+++ b/js/src/jsscope.cpp
@@ -174,11 +174,6 @@ js_NewScope(JSContext *cx, jsrefcount nrefs, JSObjectOps *ops, JSClass *clasp,
     return scope;
 }
 
-#ifdef DEBUG_SCOPE_COUNT
-extern void
-js_unlog_scope(JSScope *scope);
-#endif
-
 #if defined DEBUG || defined JS_DUMP_PROPTREE_STATS
 # include "jsprf.h"
 # define LIVE_SCOPE_METER(cx,expr) JS_LOCK_RUNTIME_VOID(cx->runtime,expr)
@@ -189,10 +184,6 @@ js_unlog_scope(JSScope *scope);
 void
 js_DestroyScope(JSContext *cx, JSScope *scope)
 {
-#ifdef DEBUG_SCOPE_COUNT
-    js_unlog_scope(scope);
-#endif
-
 #ifdef JS_THREADSAFE
     js_FinishTitle(cx, &scope->title);
 #endif
diff --git a/js/src/jstracer.cpp b/js/src/jstracer.cpp
index 324bb6287ef..289915efb41 100644
--- a/js/src/jstracer.cpp
+++ b/js/src/jstracer.cpp
@@ -5530,7 +5530,10 @@ TraceRecorder::test_property_cache(JSObject* obj, LIns* obj_ins, JSObject*& obj2
     JSAtom* atom;
     JSPropCacheEntry* entry;
     PROPERTY_CACHE_TEST(cx, pc, aobj, obj2, entry, atom);
-    if (atom) {
+    if (!atom) {
+        // Null atom means that obj2 is locked and must now be unlocked.
+        JS_UNLOCK_OBJ(cx, obj2);
+    } else {
         // Miss: pre-fill the cache for the interpreter, as well as for our needs.
         // FIXME: 452357 - correctly propagate exceptions into the interpreter from
         // js_FindPropertyHelper, js_LookupPropertyWithFlags, and elsewhere.
diff --git a/js/src/jsutil.cpp b/js/src/jsutil.cpp
index 5d7eb88d6ff..4b0a0aa6861 100644
--- a/js/src/jsutil.cpp
+++ b/js/src/jsutil.cpp
@@ -210,7 +210,7 @@ JS_DumpHistogram(JSBasicStats *bs, FILE *fp)
 
 #endif /* JS_BASIC_STATS */
 
-#if defined DEBUG_notme && defined XP_UNIX
+#if defined(DEBUG_notme) && defined(XP_UNIX)
 
 #define __USE_GNU 1
 #include <dlfcn.h>
@@ -314,7 +314,7 @@ CallTree(void **bp)
     return site;
 }
 
-JSCallsite *
+JS_FRIEND_API(JSCallsite *)
 JS_Backtrace(int skip)
 {
     void **bp, **bpdown;
@@ -342,4 +342,14 @@ JS_Backtrace(int skip)
     return CallTree(bp);
 }
 
-#endif /* DEBUG_notme && XP_UNIX */
+JS_FRIEND_API(void)
+JS_DumpBacktrace(JSCallsite *trace)
+{
+    while (trace) {
+        fprintf(stdout, "%s [%s +0x%X]\n", trace->name, trace->library,
+                trace->offset);
+        trace = trace->parent;
+    }
+}
+
+#endif /* defined(DEBUG_notme) && defined(XP_UNIX) */
diff --git a/js/src/jsutil.h b/js/src/jsutil.h
index a6c329c8a04..7d072bf125c 100644
--- a/js/src/jsutil.h
+++ b/js/src/jsutil.h
@@ -144,7 +144,7 @@ JS_DumpHistogram(JSBasicStats *bs, FILE *fp);
 #endif /* JS_BASIC_STATS */
 
 
-#ifdef XP_UNIX
+#if defined(DEBUG_notme) && defined(XP_UNIX)
 
 typedef struct JSCallsite JSCallsite;
 
@@ -159,7 +159,11 @@ struct JSCallsite {
     void        *handy;
 };
 
-extern JSCallsite *JS_Backtrace(int skip);
+extern JS_FRIEND_API(JSCallsite *)
+JS_Backtrace(int skip);
+
+extern JS_FRIEND_API(void)
+JS_DumpBacktrace(JSCallsite *trace);
 
 #endif