JDK-8288710 : Reduce the likelihood of AsyncGetCallTrace crashing due to sweeped nmethod data
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: svc
  • Affected Version: 19
  • Priority: P5
  • Status: Open
  • Resolution: Unresolved
  • Submitted: 2022-06-19
  • Updated: 2022-06-27
The Version table provides details related to the release that this issue/RFE will be addressed.

Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.

To download the current JDK release, click here.
Other
tbdUnresolved
Related Reports
Relates :  
JDK-8283849 - AsyncGetCallTrace may crash JVM on guarantee
Description
In JDK-8283849 a guarantee induced crash was fixed for situations when `CodeCache::find_blob()` would encounter a zombie method during processing the AGCT request.

While that fix removed the most frequent cause of failure related to zombie methods it is still possible for the `CodeCache::find_blob()` to return a codeblob/method which status will be changed to zombie and the code blob will be retired by the code sweeper while AGCT is still trying to access its data.

This can lead to subsequent spurious crashes when eg. AGCT attempts to access the structures of the nmethod data which were already sweeped.
Comments
Lowering the priority as this situation is very unlikely. Although it is theoretically possible to see a stale value of the code sweeper `_traversals` attribute in reality this field will be used just from the sweeper thread and the race will never be observed.
27-06-2022