JDK-8230401 : ClassLoaderData::_keep_alive is read with wrong type in c2i entry barrier
  • Type: Bug
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 14
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2019-08-30
  • Updated: 2019-09-26
  • Resolved: 2019-09-04
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JDK 14
14 b13Fixed
Related Reports
Relates :  
JDK-8162553 - Crash in class unloading due to null CLD having a zero _keep_alive value
Relates :  
JDK-8222841 - Incorrect static call stub interactions with class unloading
Description
In the c2i entry barriers used by concurrent class unloading, the _keep_alive field is read with cmpl, but it is a short. This could cause undesired results, making a method look more alive than it really is.
Comments
Interestingly, it was changed int->s2 in JDK-8162553. This change reverts it back s2->int. Is it really safe? I would have expected this to be changed to s4 to be both more resilient against C compiler interpretation of what "int" is, and making cmpl work at the same time.
06-09-2019
URL: https://hg.openjdk.java.net/jdk/jdk/rev/9ee010450e84 User: eosterlund Date: 2019-09-04 13:48:38 +0000
04-09-2019
ILW = MLM = P4
03-09-2019