On Fri, 15 Oct 2021 09:17:12 GMT, Richard Reingruber <rr...@openjdk.org> wrote:
>> Ok. So you just need to reacquire the threadLock before the `findThread()` >> call and before exiting the while loop, and hold it until after the >> `trackAppResume()` call. I guess it ok then. But this exiting of the >> handlerLock here and in `blockOnDebuggerSuspend()` is always going to arouse >> suspicion for anyone that reads the code. The first question will be if the >> lock does not need to be held here, why grab it in the first place? We know >> the answer is this lock ordering issue that turns up when `trackAppResume()` >> is later called, but this will be far from obvious to the reader. It might >> be possible to make this a bit clearer with some code restructuring, like >> maybe combining `blockOnDebuggerSuspend()` and `trackAppResume()` into one >> function (I'm not sure that this will actually help, but maybe something to >> consider), but at the very least we need some comments calling out why >> handlerLock is held in the first place and why it is ok to release it. > > I've added the comments. Maybe I should really combine > `blockOnDebuggerSuspend()` and `trackAppResume()` into one function... Hm, I think this can be simplified by swaping blockOnDebuggerSuspend() and trackAppResume(). Can't try it today but will on Monday. ------------- PR: https://git.openjdk.java.net/jdk/pull/5849
