1 /*
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25 
26 #include "precompiled.hpp"
27 #include "memory/metaspace/metaspaceArena.hpp"
28 #include "memory/metaspace/metaspaceSettings.hpp"
29 #include "memory/metaspace/testHelpers.hpp"
30 #include "utilities/debug.hpp"
31 #include "utilities/ostream.hpp"
32 
33 //#define LOG_PLEASE
34 #include "metaspaceGtestCommon.hpp"
35 #include "metaspaceGtestContexts.hpp"
36 
37 #ifdef ASSERT
38 
39 using metaspace::MetaspaceArena;
40 using metaspace::MetaspaceTestArena;
41 using metaspace::Settings;
42 
43 // Test that overwriting memory triggers an assert if allocation guards are enabled.
44 //  Note: We use TEST_VM_ASSERT_MSG. However, an assert is only triggered if allocation
45 //  guards are enabled; if guards are disabled for the gtests, this test would fail.
46 //  So for that case, we trigger a fake assert.
47 TEST_VM_ASSERT_MSG(metaspace, test_overwriter, "Corrupt block") {
48 
49   if (Settings::use_allocation_guard()) {
50     MetaspaceGtestContext context;
51     MetaspaceTestArena* arena = context.create_arena(Metaspace::StandardMetaspaceType);
52     // We allocate two blocks. We then write over the end of the first block, which
53     //  should corrupt the eyecatcher at the start of the second block.
54     // Note: there is of course no guarantee that blocks allocated sequentially are neighbors;
55     //  but in this case (clean standard-sized test arena and very small allocations) it can
56     //  be safely assumed).
57     MetaWord* p1 = arena->allocate(8);
58     MetaWord* p2 = arena->allocate(2);
59     p1[8] = (MetaWord)0x9345; // Overwriter
60     // Now we delete the arena (as happens during class unloading); this will check all
61     // block canaries and should trigger an assert (see MetaspaceArena::verify_allocation_guards()).
62     tty->print_cr("Death test, please ignore the following \"Corrupt block\" printout.");
63     delete arena;
64   } else {
65     assert(false, "Corrupt block fake message to satisfy tests");
66   }
67 
68 }
69 
70 #endif // ASSERT
71