RFR: 8329665: fatal error: memory leak: allocating without ResourceMark

[Aleksey Shipilev]

On Thu, 4 Apr 2024 16:23:50 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

> There are two places in Loom code that call f.oops_interpreted_do() to process oops in the stackChunk. Although not obvious this method seem to require to have a ResourceMark on scope and there are several contexts where these two are call where we don't have one. The reason why a ResourceMark is needed is because OopMapCache::compute_one_oop_map() might allocate from the resource area if _mask_size is > 4 * BitsPerWord, which depends on the amount of locals + expression stack of the corresponding method. But ~InterpreterOopMap already checks if the _bit_mask was allocated in the resource area and in that case it will free it. So the ResourceMark is not strictly needed except that in debug mode we will actually hit the assert if there is not one in scope when trying to allocate the _bit_mask.
> 
> Thanks,
> Patricio

TBH, seems rather odd to do this in debug mode only, and this far out. I see other places where we do `ResourceMark rm` near  `OopMapCache::compute_one_oop_map`. Should we instead do:


  // process locals & expression stack
  ResourceMark rm;
  InterpreterOopMap mask;
  if (query_oop_map_cache) {
    m->mask_for(bci, &mask);
  } else {
    OopMapCache::compute_one_oop_map(m, bci, &mask);
  }
  mask.iterate_oop(&blk);


?

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PR Review: https://git.openjdk.org/jdk/pull/18632#pullrequestreview-1982146589