RFR: 8231356: Fix broken ResourceObj::operator new[] in debug builds

Leo Korinth lkorinth at openjdk.java.net
Mon Aug 9 14:39:42 UTC 2021

ResourceObj::operator new[] calls ResourceObj::operator new (non array version). In debug builds, each resource object (on C_HEAP) will be initialized with set_allocation_type() (which is correct). What is not correct is that the constructor (and thus) set_allocation_type() is called on the array itself (which is not a ResourceObj). This initialization will be partially overwritten by the header that keeps track of the array size. When the array destructor later is called, it will also chain call the non-array destructor. In debug builds the verification of _allocation_t[0] will fail as it has been overwritten by the code that keeps track of the array size.

The following assert will fail:
assert(~(_allocation_t[0] | allocation_mask) == (uintptr_t)this, "lost resource object");

The reason that it has not been detected is that no one uses ResourceObj::operator new[] on resource objects with C_HEAP storage.


Commit messages:
 - 8231356

Changes: https://git.openjdk.java.net/jdk/pull/5055/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5055&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8231356
  Stats: 11 lines in 2 files changed: 0 ins; 9 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5055.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5055/head:pull/5055

PR: https://git.openjdk.java.net/jdk/pull/5055

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