On Thu, 25 Jan 2024 13:58:50 GMT, Tejesh R <t...@openjdk.org> wrote: >> Suggested fix [JDK-8307091](https://bugs.openjdk.org/browse/JDK-8307091) >> also created concurrent exception intermittently (monthly once/quarterly >> once) on CI system. The issue was not able to be reproduced yet, hence >> proposing an alternative fix which uses iterators to compare the List. >> CI testing shows green. > > Tejesh R has updated the pull request with a new target base due to a merge > or a rebase. The incremental webrev excludes the unrelated changes brought in > by the merge/rebase. The pull request contains three additional commits since > the last revision: > > - Revert fix 8307091 + Synchronised filecache > - Merge branch 'master' of https://git.openjdk.java.net/jdk into > branch_8323670 > - Fix
> > > I don't think we are able to trace it out, since the issue intermittent > > > and previously I had made a copy of the vector list before checking for > > > equality of the list. There was again an issue in the code which I used > > > to copy to a temporary vector. So now instead of using` > > > AbstractList.equals` I'm using iterators and comparing every element > > > within synchronized method. > > > > > > I think we should start investigating this one, probably by adding special > > delays/asserts into the JDK to track down on what threads the data is > > modified and used. > > According to my analysis above, there there are two threads. (The third > thread is also possible if `validateFileCache` is called not on EDT.) The > only thread that modifies `fileCache` is EDT with `DoChangeContents`. Then > the `ShellFolder` thread reads from `fileCache` _without synchronisation_, > which allows the contents of `fileCache` to be modified concurrently. Upon further testing, I found out that `ShellFolder.invoke` runs in the calling thread on Linux and macOS, on Windows it runs on the COM thread where Windows Shell is accessed. In addition to this, there's [`AquaFileSystemModel`](https://github.com/openjdk/jdk/blob/master/src/java.desktop/macosx/classes/com/apple/laf/AquaFileSystemModel.java). This class is used in Aqua Look-and-Feel on macOS. According to this comment https://github.com/openjdk/jdk/blob/fe0eec7e20bc4c39d6c2b58d81ffd5c0ef1fdeda/src/java.desktop/macosx/classes/com/apple/laf/AquaFileSystemModel.java#L41 the class contains portions of code copied from `BasicDirectoryModel` and therefore could have a similar synchronisation issue. ------------- PR Comment: https://git.openjdk.org/jdk/pull/17462#issuecomment-1914799788
