PartitionAlloc: Leave bucket in valid state when allocation fails

Source/wtf/PartitionAllocTest.cpp

 /*
  * Copyright (C) 2013 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
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  *     * Redistributions in binary form must reproduce the above
@@ skipping 1079 matching lines @@
     ptr = partitionAllocGeneric(genericAllocator.root(), size);
     EXPECT_TRUE(ptr);
     partitionFreeGeneric(genericAllocator.root(), ptr);
 
     EXPECT_TRUE(bucket->activePagesHead);
     EXPECT_TRUE(bucket->freePagesHead);
 
     TestShutdown();
 }
 
+// Tests that if an allocation fails in "return null" mode, repeating it doesn't
+// crash, and still returns null.  The test allocates 6 GB of memory in 512 kB
+// blocks. This may never fail on 64-bit systems, in which case this test fails

[Jens Widell, 2014/10/22 19:40:12]

To make these allocations fail on 64-bit, I've been using "ulimit -v 2000000" to
set a 2 GB address space limit before running wtf_unittests. Is there anything
in the testing framework/infrastructure that could be used to the same effect to
ensure this test is meaningful?

Oh, if only we hadn't just dropped PartitionAlloc's 2 GB address space limit...
:-)

+// to test what it sets out to test.
+TEST(PartitionAllocTest, RepeatedReturnNull)
+{
+    TestSetup();
+
+    void* ptrs[8192];
+    int i;
+
+    for (i = 0; i < 6144; ++i) {
+        ptrs[i] = partitionAllocGenericFlags(genericAllocator.root(), WTF::PartitionAllocReturnNull, 512*1024);
+        if (!ptrs[i]) {
+            ptrs[i] = partitionAllocGenericFlags(genericAllocator.root(), WTF::PartitionAllocReturnNull, 512*1024);
+            EXPECT_FALSE(ptrs[i]);
+            break;
+        }
+    }
+
+    for (--i; i >= 0; --i) {
+        partitionFreeGeneric(genericAllocator.root(), ptrs[i]);
+        ptrs[i] = partitionAllocGenericFlags(genericAllocator.root(), WTF::PartitionAllocReturnNull, 512*1024);
+        partitionFreeGeneric(genericAllocator.root(), ptrs[i]);
+    }
+
+    TestShutdown();
+}
+
 #if !OS(ANDROID)
 
 // Make sure that malloc(-1) dies.
 // In the past, we had an integer overflow that would alias malloc(-1) to
 // malloc(0), which is not good.
 TEST(PartitionAllocDeathTest, LargeAllocs)
 {
     TestSetup();
     // Largest alloc.
     EXPECT_DEATH(partitionAllocGeneric(genericAllocator.root(), static_cast<size_t>(-1)), "");
@@ skipping 79 matching lines @@
     EXPECT_EQ(32u, WTF::countLeadingZerosSizet(0u));
     EXPECT_EQ(31u, WTF::countLeadingZerosSizet(1u));
     EXPECT_EQ(1u, WTF::countLeadingZerosSizet(1u << 30));
     EXPECT_EQ(0u, WTF::countLeadingZerosSizet(1u << 31));
 #endif
 }
 
 } // namespace
 
 #endif // !defined(MEMORY_TOOL_REPLACES_ALLOCATOR)