JDK-8135018 : AARCH64: Missing memory barriers for CMS collector
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • CPU: aarch64
  • Submitted: 2015-09-03
  • Updated: 2021-02-01
  • Resolved: 2015-09-24
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JDK 9 Other
9 b89Fixed openjdk8u292Fixed
Related Reports
Duplicate :  
JDK-8138891 - C1: Missing release memory barrier in C1's CMS post-barrier
Relates :  
JDK-8257192 - Integrate AArch64 JIT port into 8u
Relates :  
JDK-8129325 - UseCondCardMark broken in conjunction with CMS on SPARC
Description
While we have StoreStore barriers to keep card table updates in the right place in C2, we do not have them in C1 or in the interpreter. This is a window in which concurrent marking the old generation may see a null pointer instead of a real object pointer and miss marking an object.
Comments
noreg-hard justification: It is very hard to write a regression test for this issue as this is entirely dependent on timing. Further we have never actually observed a failure because of that.
24-09-2015