Crash in fluid.bufstats

tremblap · February 7, 2025, 12:45pm

can you make a real bug report on github please so I can chase this?

rodrigo.constanzo · February 7, 2025, 1:06pm

Here you go:

github.com/flucoma/flucoma-max

Bug: fluid.bufstats~ can crash when mixing threads

opened 01:06PM - 07 Feb 25 UTC

rconstanzo

bug

### Please tell us what you were doing! You can include code and files by drag a…nd dropping them into the text area. It seems that `fluid.bufstats~` can insta-crash when it is getting messages from mixed threads, specifically receiving weights in it's right-most inlet in the high-priority thread, while the object is in `@blocking 1` and then also receiving buffers upstream from the high-priority thread. So I think the steps are: 1. have `fluid.bufstats~ @blocking 1` 2. send weights buffer to right inlet from high-priority thread 3. send buffer into left inlet from high-priority thread Sometimes this gives an `Invalid weights` error message (as mentioned below) but other times it will just crash, presumably when read/writing from unsafe memory. This is happening in the patch outlined in this thread: https://discourse.flucoma.org/t/creating-a-filter-from-spectral-moments-fluid-spectralshape/ Specifically this version of the patch: https://discourse.flucoma.org/uploads/short-url/nkoDHX3alGOt8e2sudrKHQsmq3J.zip The offending abstraction is `dk.spectralshapeframe` which has three instances of `fluid.stats~` in it, and only one of which was having it's `@blocking` mode updated automatically (I missed the connection when building the patch). If you run the patch for any amount of time you will see the error messages, and eventually a crash. Here's a crash report: [bufstats crash.zip](https://github.com/user-attachments/files/18706952/bufstats.crash.zip) ### What was the expected result? Complaining about threading, which it did do as well: > fluid.bufstats~: Invalid weights But sometimes it would not complain and instead crash. ### What was the actual result? An insta-crash. ### What operating system were you using? Mac ### Operating system version macOS 15.2 ### FluCoMa Version 1.0.8+sha.0a9327e.core.sha.7dfcc220

I think it’s this:

have fluid.bufstats~ @blocking 1
send weights buffer to right inlet from high-priority thread
send buffer into left inlet from high-priority thread

edit:
If you downloaded the updated abstraction two posts up, re-download it as it was still thread unsafe (I missed a @blocking change cable in the previous edit).