lrdp-v2: Correct SLUB track address calculation

SLUB allocation and freeing tracking storage address calculation
doesn't take into account the length of the red zone header,
resulting in incorrect stack dump when Linux RAM dump parser is
used to parse(with --slabinfo option)dumps generated with
SLUB_DEBUG options enabled.

Change-Id: I50f4c6d304ff1ecd57bfddb1bfa9441ff5cb3ac1

linux-ramdump-parser-v2/parsers/slabinfo.py

@@ -76,6 +76,11 @@ class kmem_cache(object):
         self.inuse = ramdump.read_int(addr + offset)
         if self.inuse is None:
             return
+        offset = ramdump.field_offset(
+            'struct kmem_cache', 'red_left_pad')
+        self.red_left_pad = ramdump.read_int(addr + offset)
+        if self.red_left_pad is None:
+            self.red_left_pad = 0
         self.addr = addr
         self.valid = True
 
@@ -147,9 +152,9 @@ class Slabinfo(RamParser):
     def get_track(self, ramdump,  slab, obj, track_type):
         track_size = g_offsetof.sizeof_struct_track
         if slab.offset != 0:
-            p = obj + slab.offset + g_offsetof.sizeof_void_pointer
+            p = obj + slab.red_left_pad + slab.offset + g_offsetof.sizeof_void_pointer
         else:
-            p = obj + slab.inuse
+            p = obj + slab.red_left_pad + slab.inuse
         return p + track_type * track_size
 
     def extract_callstack(self, ramdump, stack, out_file):