RFR: 8360664: Null pointer dereference in src/hotspot/share/prims/jvmtiTagMap.cpp in IterateOverHeapObjectClosure::do_object() [v3]

[David Holmes]

On Mon, 30 Jun 2025 13:03:23 GMT, Artem Semenov <asemenov at openjdk.org> wrote:

>> The defect has been detected and confirmed in the function ```IterateOverHeapObjectClosure::do_object()``` located in the file ```src/hotspot/share/prims/jvmtiTagMap.cpp``` with static code analysis. This defect can potentially lead to a null pointer dereference.
>> 
>> The pointer ```oop o``` is passed to the constructor of the CallbackWrapper class, where it is dereferenced without a null check.
>
> Artem Semenov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   changed if tu assert

src/hotspot/share/prims/jvmtiTagMap.cpp line 947:

> 945: // invoked for each object in the heap
> 946: void IterateOverHeapObjectClosure::do_object(oop o) {
> 947:   assert(o != nullptr, "Parameter 'o' must not be null!");

Suggestion:

  assert(o != nullptr, "Heap iteration should never produce null");

Same with the other assertion please. Though as @plummercj  states I don't see how this will help with the static analysis tool.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26002#discussion_r2176326686