RFR: 8297923: java.awt.ScrollPane broken after multiple scroll up/down

Tue Sep 5 13:14:05 UTC 2023

On Tue, 6 Jun 2023 21:00:20 GMT, Phil Race <prr at openjdk.org> wrote:

> I wonder if we have any other leaks due to similar thread mis-usage ? Seems possible since this one went un-detected for a long time and its probably one of the easier ones to get to run out of GDI objects.

@prrace Potentially, all the usages of `SyncCall` are at risk.

https://github.com/openjdk/jdk/blob/ed2b4673de6893047407c61f82b5e68741459876/src/java.desktop/windows/native/libawt/windows/awt_Toolkit.cpp#L1870-L1878

It does not even synchronise the threads. So, there could be other leaks or issues with memory visibility.

I think this scenario led to leaks because it also modified the position of the horizontal scroll bar, which started animation provided by visual styles. The animation never got a change to complete before another update came. The issue wasn't reproducible if there was only vertical scroll bar which was being dragged.

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PR Comment: https://git.openjdk.org/jdk/pull/14338#issuecomment-1706593274