RFR: 8300696 : [AIX] AttachReturnError fails

[Thomas Stuefe]

On Mon, 23 Jan 2023 09:36:35 GMT, Deepa Kumari <duke at openjdk.org> wrote:

> AttachReturnError.java fails because "VM.dynlibs" prints a list of loaded dynamic libs referring to a cache. The cache may contain stale entries related to unloaded libraries (libReturnError.so in this case). Reloading this cache after unloading libraries solves the problem.
> 
> Reported Issue : [JDK-8300696](https://bugs.openjdk.org/browse/JDK-8300696)

@deepa181  Good catch. This bug is almost 20 years old.

Side note: we synchronize this cache with a homegrown pthread-mutex class (see misc_aix.hpp). I did this with the original AIX port to keep merging simple - we never expected to contribute this coding, OpenJDK did not yet exist.

But it may be useful to use real hotspot Mutexes instead since you get deadlock recognition.

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PR: https://git.openjdk.org/jdk/pull/12138