JDK-8057038 : Speculative traps not robust when compilation and class unloading are concurrent
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 9
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2014-09-02
  • Updated: 2021-09-20
  • Resolved: 2014-09-03
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JDK 8 JDK 9 Other
8u321Fixed 9 b31Fixed openjdk8u322Unresolved
Related Reports
Relates :  
JDK-8139247 - Improper locking of MethodData::_extra_data_lock
Relates :  
JDK-8216427 - ciMethodData::load_extra_data() does not always unpack the last entry
Relates :  
JDK-8215889 - assert(!_unloading) failed: This oop is not available to unloading class loader data with ZGC
Description
Speculative traps recorded in a MethodData can be removed at a safepoint. During a compilation, as a MethodData is copied and translated by a compiler thread to build a ciMethodData, a safepoint can occur as speculative traps are being copied, and not yet copied speculative traps may be removed. That changes the layout of the traps. The loop doing the copying doesn't handle it currently.
Comments
URL: http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/5a313cfb5637 User: lana Date: 2014-09-17 17:25:47 +0000
17-09-2014
ILW=possible incorrect behaviour, race, none=MLH=P4
04-09-2014
URL: http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/5a313cfb5637 User: roland Date: 2014-09-03 17:01:26 +0000
03-09-2014
regarding lack of test case: this requires class unloading to happen concurrently with compilation and the compiler thread to safepoint at a particular point in the code. Very hard to achieve with a simple test case.
03-09-2014