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  1. JDK
  2. JDK-8266432

ZGC: GC allocation stalls can trigger deadlocks

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 17
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
      gc
    • Resolved In Build:
      b21
    • Verification:
      Verified

      Description

      A deadlock can happen when a relocating thread holds the lock and tries to log information about the current thread, which can trigger a load barrier and a secondary relocation. The first relocation is holding the _ref_lock and the second relocation hangs when trying to reacquiring it. This is the stack trace:

      #1 0x00007ff375c1fc90 in os::PlatformMonitor::wait
      #2 0x00007ff3760cbf92 in ZForwarding::wait_page_released
      #3 0x00007ff376118065 in ZRelocate::relocate_object
      #4 0x00007ff374f7097b in AccessInternal::PostRuntimeDispatch<ZBarrierSet::AccessBarrier<286790ul, ZBarrierSet>,
      #5 0x00007ff375176134 in oopDesc::obj_field
      #6 0x00007ff37551c5cb in java_lang_Thread::name
      #7 0x00007ff375f2e7ee in JavaThread::get_thread_name_string
      #8 0x00007ff376126323 in ZStatPhase::log_end
      #9 0x00007ff3761272e8 in ZStatCriticalPhase::register_end
      #10 0x00007ff3760cc0b0 in ZForwarding::wait_page_released
      #11 0x00007ff376118065 in ZRelocate::relocate_object
      #12 0x00007ff3760989c5 in ZLoadBarrierOopClosure::do_oop
      #13 0x00007ff375408ca8 in HandleArea::oops_do
      #14 0x00007ff375f2e0e9 in JavaThread::oops_do_no_frames

      This started to happen after:
      8261759: ZGC: ZWorker Threads Continue Marking After System.exit() called

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              Assignee:
              stefank Stefan Karlsson
              Reporter:
              stefank Stefan Karlsson
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                Dates

                Created:
                Updated:
                Resolved: