[PATCH] Fix realloc'ing a freed pointer

[Timur Iskhodzhanov]

Hi kcc,

See https://code.google.com/p/address-sanitizer/issues/detail?id=187

http://llvm-reviews.chandlerc.com/D818

Files:
  tests/asan_test.cc
  asan_allocator2.cc

Index: tests/asan_test.cc
===================================================================
--- tests/asan_test.cc
+++ tests/asan_test.cc
@@ -353,6 +353,13 @@
   free(ptr2);
 }
 
+TEST(AddressSanitizer, ReallocFreedPointerTest) {
+  void *ptr = Ident(malloc(42));
+  ASSERT_TRUE(NULL != ptr);
+  free(ptr);
+  EXPECT_DEATH(ptr = realloc(ptr, 77), "attempting double-free");
+}
+
 TEST(AddressSanitizer, ZeroSizeMallocTest) {
   // Test that malloc(0) and similar functions don't return NULL.
   void *ptr = Ident(malloc(0));
Index: asan_allocator2.cc
===================================================================
--- asan_allocator2.cc
+++ asan_allocator2.cc
@@ -488,6 +488,9 @@
   thread_stats.reallocs++;
   thread_stats.realloced += new_size;
 
+  if (m->chunk_state == CHUNK_QUARANTINE)
+    ReportDoubleFree((uptr)old_ptr, stack);
+
   CHECK_EQ(m->chunk_state, CHUNK_ALLOCATED);
   uptr old_size = m->UsedSize();
   uptr memcpy_size = Min(new_size, old_size);
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