Hi Sam, You should definitely file a feature request for that. I understand your use case and I see how one could assume that this would work. I suppose the behavior change comes from this CL in particular [0]. And that change was made under the assumption that calls would be on the right thread. There may be other (less obvious) issues with this method on concurrent threads as well. So if we want to support concurrent usage we should check the rest of the method as well and have some test coverage for this. Alternatively you could also invoke that method on the right thread (e.g. through posting a task) and let it report back the result as well.
Cheers, Dominik 0: https://chromium-review.googlesource.com/c/v8/v8/+/4946715 On Friday, June 7, 2024 at 10:24:22 AM UTC+2 sjtuc...@gmail.com wrote: > Hi Dominik, > > I forgot to mention the OS is Windows 10 x86_64. Monitoring the heap > statistics in another thread used to work well before this change. > > I wonder why this call has to be in the same thread. Consider V8 is used > in an online service (Node.js). The service provider usually owns a > dashboard showing the server farm statistics including the Node.js heap > usage. I'm afraid the data has to be coming from another thread hitting the > same V8 isolate via this call. > > For now, the Node.js v20.14.0 LTS (V8 v11.3.244.8) hasn't picked up this > change, so this issue doesn't impact the majority of users. I removed this > check in my private build and this API works as usual now. > > Please consider this feature as one of the key features in online services > and find a better way to resolve it. > > Thank you, > Sam > > > On Friday, June 7, 2024 at 3:54:20 PM UTC+8 dinf...@chromium.org wrote: > >> Hi, >> >> I cannot reproduce this crash locally (neither on 12.5.227.6 nor on >> tip-of-tree). I suspect what's going on here is that you are using >> GetHeapStatistics from a second thread which is not supported. This likely >> causes this particular CHECK failure. The fix for this would be to invoke >> GetHeapStatistics on thread 1 as well. >> >> Cheers, >> Dominik >> >> >> On Friday, June 7, 2024 at 6:22:01 AM UTC+2 sjtuc...@gmail.com wrote: >> >>> Hi V8 Dev, >>> >>> I'd like to report a potential bug in ConcurrentMarking::RunMajor(). >>> >>> *Fatal Error* >>> # >>> # Fatal error in , line 0 >>> # Check failed: !IsFreeSpaceOrFillerMap(map). >>> # >>> # >>> # >>> #FailureMessage Object: 00000083D21FF440 >>> ==== C stack trace =============================== >>> CrashForExceptionInNonABICompliantCodeRange [0x00007FFF4AA557BB+ >>> 1514667] >>> (No symbol) [0x00007FFF4A77D497] >>> (No symbol) [0x00007FFF4A820BBA] >>> CrashForExceptionInNonABICompliantCodeRange [0x00007FFF4AB234A1+ >>> 2357649] >>> CrashForExceptionInNonABICompliantCodeRange [0x00007FFF4AB3AB62+ >>> 2453586] >>> CrashForExceptionInNonABICompliantCodeRange [0x00007FFF4AA570A6+ >>> 1521046] >>> CrashForExceptionInNonABICompliantCodeRange [0x00007FFF4AA5A466+ >>> 1534294] >>> >>> *Reproduce* >>> >>> 1. Set max heap size to 8096 >>> 2. Start thread 1 and execute the following JS code. >>> var a = []; >>> for (let i = 0; i < 100000000; i++) { >>> a.push({test:'test'}); >>> } >>> 3. Start thread 2 and call v8Isolate->GetHeapStatistics() >>> periodically. >>> >>> There is a high chance that V8 will crash with the fatal error posted >>> above. >>> >>> *Analysis* >>> I reviewed the source code of 12.5.227.6 and found there is only one >>> call to IsFreeSpaceOrFillerMap() inside ConcurrentMarking::RunMajor() as >>> follows. >>> [image: 01.png] >>> >>> It seems this check is not always valid when that V8 isolate is busy >>> allocating memory. It used to be working well before this check was added. >>> >>> Please check this issue out. >>> >>> Thank you, >>> Sam >>> >> -- -- v8-dev mailing list v8-dev@googlegroups.com http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-dev+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/v8-dev/dc3f8047-4863-47cb-bc10-97b89db80d21n%40googlegroups.com.
