RFR: 8269091: javax/sound/sampled/Clip/SetPositionHang.java failed with ArrayIndexOutOfBoundsException: Array index out of range: -4

[Sergey Bylokhov]

On Thu, 10 Feb 2022 23:57:29 GMT, Phil Race <prr at openjdk.org> wrote:

> This test has started failing since we got M1 macs to test on. I don't think we've ever seen this failure elsewhere.
> I don't know what it is about that architecture that makes it more likely but I can see how it can happen when multiple threads are using the same instance. 
> 
>                     if (newFramePosition >= 0) { 
>                         clipBytePosition = newFramePosition * frameSize; 
>                         newFramePosition = -1; 
>                     } 
> 
> newFramePosition is declared volatile which does make it quite possible that after the read and before the use it will have changed.
> 
> The fix just synchronizes this block to prevent it.

src/java.desktop/share/classes/com/sun/media/sound/DirectAudioDevice.java line 1300:

> 1298:                 }
> 1299:                 while (doIO && thread == curThread) {
> 1300:                     synchronized (this) {

Maybe instead of synchronization we can read it to the local variable,then use, then reset to -1? This class already has many different locks used for synchronization and this one add another one for "this".

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PR: https://git.openjdk.java.net/jdk/pull/7436