Merge r180430 - bmalloc should implement malloc introspection (to sto…

…p false-positive leaks when MallocStackLogging is off)

https://bugs.webkit.org/show_bug.cgi?id=141802

Reviewed by Andreas Kling.

Rolling back in with a fix for a crash seen while using GuardMalloc.

* bmalloc/VMHeap.cpp:
(bmalloc::VMHeap::grow):
* bmalloc/VMHeap.h:
* bmalloc/Zone.cpp: Re-land the old patch.

(bmalloc::Zone::size): Be sure to implement the size() function since
it's accessible indirectly via the malloc_zone_from_ptr public API --
and GuardMalloc calls it all the time.

(bmalloc::Zone::Zone):
* bmalloc/Zone.h: Re-land the old patch.

Source/bmalloc/ChangeLog

@@ -1,3 +1,39 @@
+2015-02-20  Geoffrey Garen  <ggaren@apple.com>
+
+        bmalloc should implement malloc introspection (to stop false-positive leaks when MallocStackLogging is off)
+        https://bugs.webkit.org/show_bug.cgi?id=141802
+
+        Reviewed by Andreas Kling.
+
+        Rolling back in with a fix for a crash seen while using GuardMalloc.
+
+        * bmalloc/VMHeap.cpp:
+        (bmalloc::VMHeap::grow):
+        * bmalloc/VMHeap.h:
+        * bmalloc/Zone.cpp: Re-land the old patch.
+
+        (bmalloc::Zone::size): Be sure to implement the size() function since
+        it's accessible indirectly via the malloc_zone_from_ptr public API --
+        and GuardMalloc calls it all the time.
+
+        (bmalloc::Zone::Zone):
+        * bmalloc/Zone.h: Re-land the old patch.
+
+2015-02-19  Commit Queue  <commit-queue@webkit.org>
+
+        Unreviewed, rolling out r180363.
+        https://bugs.webkit.org/show_bug.cgi?id=141814
+
+        Caused >50 crashes when running LayoutTests in GuardMalloc or
+        ASAN modes. (Requested by jernoble on #webkit).
+
+        Reverted changeset:
+
+        "bmalloc should implement malloc introspection (to stop false-
+        positive leaks when MallocStackLogging is off)"
+        https://bugs.webkit.org/show_bug.cgi?id=141802
+        http://trac.webkit.org/changeset/180363
+
 2015-02-19  Geoffrey Garen  <ggaren@apple.com>
 
         bmalloc should implement malloc introspection (to stop false-positive leaks when MallocStackLogging is off)

Source/bmalloc/bmalloc/Zone.cpp

@@ -42,6 +42,13 @@ template<typename T> static void remoteRead(task_t task, memory_reader_t reader,
     memcpy(&result, tmp, sizeof(T));
 }
 
+// Support malloc_zone_from_ptr, which calls size() on each registered zone.
+size_t Zone::size(malloc_zone_t*, const void*)
+{
+    // Our zone is not public API, so no pointer can belong to us.
+    return 0;
+}
+
 // This function runs inside the leaks process.
 kern_return_t Zone::enumerator(task_t task, void* context, unsigned type_mask, vm_address_t zone_address, memory_reader_t reader, vm_range_recorder_t recorder)
 {
@@ -63,9 +70,10 @@ kern_return_t Zone::enumerator(task_t task, void* context, unsigned type_mask, v
 
 Zone::Zone()
 {
-    version = 4;
-    zone_name = "WebKit Malloc";
-    introspect = &bmalloc::introspect;
+    malloc_zone_t::size = size;
+    malloc_zone_t::zone_name = "WebKit Malloc";
+    malloc_zone_t::introspect = &bmalloc::introspect;
+    malloc_zone_t::version = 4;
     malloc_zone_register(this);
 }
 

Source/bmalloc/bmalloc/Zone.h

@@ -38,6 +38,7 @@ class Zone : public malloc_zone_t {
     // Enough capacity to track a 64GB heap, so probably enough for anything.
     static const size_t capacity = 2048;
 
+    static size_t size(malloc_zone_t*, const void*);
     static kern_return_t enumerator(task_t, void* context, unsigned type_mask, vm_address_t, memory_reader_t, vm_range_recorder_t);
 
     Zone();