Fix mmap region iteration while no regions are recorded.

third_party/tcmalloc/chromium/src/memory_region_map.cc

 /* Copyright (c) 2006, Google Inc.
  * All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  * 
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 213 matching lines @@
     // regions_ on demand for us.
   if (use_buckets) {
     const int table_bytes = kHashTableSize * sizeof(*bucket_table_);
     recursive_insert = true;
     bucket_table_ = static_cast<HeapProfileBucket**>(
         MyAllocator::Allocate(table_bytes));
     recursive_insert = false;
     memset(bucket_table_, 0, table_bytes);
     num_buckets_ = 0;
   }
+  if (regions_ == NULL)  // init regions_
+    InitRegionSetLocked();
   Unlock();
   RAW_VLOG(10, "MemoryRegionMap Init done");
 }
 
 bool MemoryRegionMap::Shutdown() {
   RAW_VLOG(10, "MemoryRegionMap Shutdown");
   Lock();
   RAW_CHECK(client_count_ > 0, "");
   client_count_ -= 1;
   if (client_count_ != 0) {  // not last client; need not really shutdown
@@ skipping 282 matching lines @@
     memset(new_bucket, 0, sizeof(*new_bucket));
     new_bucket->hash = bucket.hash;
     new_bucket->depth = bucket.depth;
     new_bucket->stack = key_copy;
     new_bucket->next = bucket_table_[hash_index];
     bucket_table_[hash_index] = new_bucket;
     ++num_buckets_;
   }
 }
 
+inline void MemoryRegionMap::InitRegionSetLocked() {
+  RAW_VLOG(12, "Initializing region set");
+  regions_ = regions_rep.region_set();
+  recursive_insert = true;
+  new(regions_) RegionSet();
+  HandleSavedRegionsLocked(&DoInsertRegionLocked);
+  recursive_insert = false;
+}
+
 inline void MemoryRegionMap::InsertRegionLocked(const Region& region) {
   RAW_CHECK(LockIsHeld(), "should be held (by this thread)");
   // We can be called recursively, because RegionSet constructor
   // and DoInsertRegionLocked() (called below) can call the allocator.
   // recursive_insert tells us if that's the case. When this happens,
   // region insertion information is recorded in saved_regions[],
   // and taken into account when the recursion unwinds.
   // Do the insert:
   if (recursive_insert) {  // recursion: save in saved_regions
     RAW_VLOG(12, "Saving recursive insert of region %p..%p from %p",
                 reinterpret_cast<void*>(region.start_addr),
                 reinterpret_cast<void*>(region.end_addr),
                 reinterpret_cast<void*>(region.caller()));
     RAW_CHECK(saved_regions_count < arraysize(saved_regions), "");
     // Copy 'region' to saved_regions[saved_regions_count]
     // together with the contents of its call_stack,
     // then increment saved_regions_count.
     saved_regions[saved_regions_count++] = region;
   } else {  // not a recusrive call
-    if (regions_ == NULL) {  // init regions_
-      RAW_VLOG(12, "Initializing region set");
-      regions_ = regions_rep.region_set();
-      recursive_insert = true;
-      new(regions_) RegionSet();
-      HandleSavedRegionsLocked(&DoInsertRegionLocked);
-      recursive_insert = false;
-    }
+    if (regions_ == NULL)  // init regions_
+      InitRegionSetLocked();
     recursive_insert = true;
     // Do the actual insertion work to put new regions into regions_:
     DoInsertRegionLocked(region);
     HandleSavedRegionsLocked(&DoInsertRegionLocked);
     recursive_insert = false;
   }
 }
 
 // We strip out different number of stack frames in debug mode
 // because less inlining happens in that case
@@ skipping 228 matching lines @@
        r != regions_->end(); ++r) {
     RAW_LOG(INFO, "Memory region 0x%"PRIxPTR"..0x%"PRIxPTR" "
                   "from 0x%"PRIxPTR" stack=%d",
                   r->start_addr, r->end_addr, r->caller(), r->is_stack);
     RAW_CHECK(previous < r->end_addr, "wow, we messed up the set order");
       // this must be caused by uncontrolled recursive operations on regions_
     previous = r->end_addr;
   }
   RAW_LOG(INFO, "End of regions list");
 }