Game crashes with CET with JIT enabled when using special k (mod).

[tscolin]

Bug

Operating system: Windows 11 24H2
Game version: 2.21
CET version: Latest
GPU: 4090

Description

Game crashes when using CET with a universal mod called Special K. The game only crashes when using JIT from CET settings.

Expected behaviour

Game should run with Special K opperational.

Reproduction

Install special k. Go into steam cyberpunk properties, then add to command line: skif %command%. If JIT is enabled, game crashes. If disabled game runs.

Workaround

Disable JIT in CET settings. OR use SK 24.8.11.1 (thanks Rool-IO)

[Rool-IO]

Can't imagine how thankful I am for you opening that issue... I can confirm this setting is indeed the culprit for a long standing CTD at launch I've had since post SK 24.8.11.1 (last working version with JIT enabled).

@Kaldaien , hope you won't mind peeking into this one and maybe find a fix/workaround to implement in SK &/or CET as the JIT compiler is indeed making mods a little more performant which is quite helpful when piling them up by dozens when not hundreds.

[WSSDude]

Little more performant is an understatement. Unsure why that would be the case though, could be some multithreading issue with some mod you use (observes/overrides may cause this technically), unlikely CET itself being the issue here but could be the case also somehow...

Guess with JIT something happens so fast it causes some weird race condition elsewhere.

[WSSDude]

Thinking if this should be kept open or not... Guess we can leave it open for now but unless it is confirmed to happen with just CET and lets say SpecialK as it seems to be the trigger, not really considering this as a CET bug. Needs to be verified by someone with just those 2 mods ideally to see if there truly isnt something else going on with some other mod in the mix.

[Rool-IO]

Doesn't matter if it's a CET bug per say or not imo.
There's a bug and it's gone when JIT is disabled so the trigger is the JIT compiler. Even if it's due to another mod (in which case trying with just CET and SK would be kind of a pointless test anyway), the fact remains JIT enabled allows that bug to happen so something is on CET. That having SK in the mix causes that bug to cause a crash is indicative it's both serious and should be investigated regardless of where it actually stems from and since the crash occurs at launch, it should be easy enough to diagnose with the proper method and guidance (or so I'd hope). All I can say as of now is that CTD crash reporter stacktrace always says "a heap was corrupted".

[WSSDude]

How does it not matter from what I wrote? We have 0 control over when Override or Observe is executed. Game is heavily multithreaded when it comes to scripts. These were modders responsibility to make sure they are stable. We cant say what is used inside of the function and if it is safe to use there. In that case, it is not CET issue because CET is just physically incapable of doing that in any way and never claimed it does. Its not possible by any normal means.

[WSSDude]

Therefore, if it is happening with some random mod on top, it is not CET issue but likely something other mod is doing. SpecialK and CET alone would be different case as that would mean something purely native is causing this without outside influence. Which yeah, I kinda dont see how but dont dismiss it outright yet, want it confirmed.

[Rool-IO]

It doesn't matter to chit chat about whether it's a CET issue or not is my point. This is just deflecting the problem away when it should be troubleshooted (yes it's the CET GitHub but we talk about a modded game install, not some random standalone program its devs want to make sure has a bug itself or not).
Otherwise nothing will get fixed ever around that particular CTD inducing bug.
Anyway, please help me help you figuring out what exactly is happening here.
My goal here is just to get a more stable game & mod assortment and having found the one trigger/revealer to this CTD bug is already a lot imo so I'd rather contribute to fixing it, wherever & whatever it stems from, instead of chit chatting technicalities.

(Please don't read this wrong or take it personally, nothing malicious in my writing even if it might come across a bit dry.)

[WSSDude]

Nah none taken. Just really problematic if mod does it cause we cant influence that still, not trying to deflect necessarily here.

Still need to check CET + SpecialK alone first, then try to identify what mod causes it IF that initial check proves it is something happening from Lua side (which disabling JIT points to).

After we have mod, we can see what from that mod causes an issue, Id suspect either of the Observe or Override call that mod uses. If not, that is truly problematic and should be double-checked if it can be prevented on CET side.

In other words, we have to bisect. Logging doesnt work in crash scenario unfortunately so having some global test log wouldnt help much in that particular instance, only way is to try to identify the culprit and obv, we dont know what mods you both have installed.

[WSSDude]

We should somehow try to fix the logging tbh, my attempts in the past didnt work due to spdlog being multithreaded... Flushing occures on other thread and during crash may end up unflushed unless we somehow hook the handler and ensure proper spdlog shutdown. Unless there is some other way, I dont know about any.

[Rool-IO]

I'll get back to you with whatever I find when I get the time to do that initial test (which I'd bet won't cause a crash as another user on SK's discord reported they could boot with recent SKs and CET's JIT enabled - btw, I'm using this CET build by @Kaldaien but I'll update to 1.35.1 - which wasn't pushed to Nexus and didn't have an attached zip yet back when I saw its release notification here, had checked it too early ig - before testing proper) and bisect exhaustively later this week.
Hopefully very soon

[WSSDude]

Cant seem to access that link for some reason but isnt it just #1003 PR?

That should be present in latest release, would prefer to test with our builds than builds I dont even know what is in them tbh.

[WSSDude]

And huh, you right, not on Nexus. Unsure why now tbh 🤔

Mouse cursor is bugged a bit atm due to me trying to fix the ShowCursor in a bit better way (as #1003 is just a patch of sorts for that in the end, it still spammed cursor calls... but me fixing the spam broke other things so cursor atm is not working proper)

Maybe it is not there cause of that, would have to ask yamashi.

[WSSDude]

@Rool-IO you could before bisecting try to send the crash report game makes if crash reporter pops up for this one, but do it please with the latest release. Maybe it could proof to be a shortcut, although have a feel it wont be useful much, they rarely helped in the past.

[Rool-IO]

Just did a quick try with 1.35.1's JIT off (still working :) ) then on (still not) and it's the exact same heap corruption message in the stacktrace. Attached is the game's crash report. Fingers crossed it's got anything useful.

Cyberpunk2077-20250429-105852-53448-50156.zip

(As for Kaldaien's build, I think it's only his merged PR indeed)