On Mon, 16 May 2022 15:14:25 GMT, Jaroslav Bachorik <jbacho...@openjdk.org> wrote:
>> A gist of the fix is to allow relaxed special handling of code blob lookup >> when done for ASGCT. >> >> Currently, a guarantee will fail when we happen to hit a zombie method which >> is still on stack. While this would indicate a serious error for the normal >> execution flow, in case of ASGCT being in progress when the executing thread >> can be expected at any possible method this is something which may happen >> and we really should not take the profiled JVM down due to it. >> >> <hr> >> Unfortunately, I am not able to create a simple reproducer for the crash >> other that testing in our production where the crash is happening >> sporadically. >> However, thanks to @parttimenerd and his [ASGCT stress >> test](https://github.com/parttimenerd/asgct2-tester.git) the problem can be >> reproduced quite reliably. >> >> <br><br> >> >> _Note: This is a followup PR for #8061_ > > Jaroslav Bachorik has updated the pull request incrementally with one > additional commit since the last revision: > > Restore the original find_blob behavior regarding dead blobs src/hotspot/share/prims/forte.hpp line 53: > 51: ASGCTMark() : ASGCTMark(JavaThread::current()) {} > 52: ~ASGCTMark() { > 53: JavaThread::current()->set_in_asgct(false); You can't call `JavaThread::current()` in any of this code as it is not safe from a signal handling context. (There is an existing use in ASGCT that is also unsafe.) I suggest not having the no-arg constructor and require the current JavaThread, or null, to be passed in (having already been safely obtained by the caller). You can then assert using `Thread::current_or_null_safe()`. Personally I find the ASGCTMark complete overkill for this situation as there is only ever going to be a single use - sorry @tstuefe - it is just complicating things IMO. src/hotspot/share/runtime/thread.hpp line 1650: > 1648: static void vm_exit_on_osthread_failure(JavaThread* thread); > 1649: > 1650: Don't need two blank lines. Thanks. ------------- PR: https://git.openjdk.java.net/jdk/pull/8549
