Panda3D fails to get LightMutexHolder lock.

[ponyboy837]

Panda3D seems to fail trying to get a LightMutexHolder lock (https://prnt.sc/feijna) in MouseWatcher when trying to replace a group and returns a memory violation error instead.

The project this was found in is located here (https://github.com/theclashingfritz/libotp)

I don't know much on why this actually happens so feel free to look into it.

[rdb (rdb)]

The key clue here is in the inspector which shows that "this" is 0. So, it is being called on a NULL pointer, which is why accessing the _lock member fails.

However, looking in pgTop.cxx cull_callback function, it seems there is already an assert to check whether it is NULL before calling replace_group. Are you compiling without assertions, perchance?

[ponyboy837 (ponyboy837)]

I'm not calling it at all. The graphics engine is what ends up calling it which is a issue. A bit a odd one.

[ponyboy837 (ponyboy837)]

Also my panda3d is compiled with assertions. (That's the reason why i need to show and hide Mouse Watcher regions to add a region without crashing oddly enough)

[ponyboy837 (ponyboy837)]

This doesn't look good at all. https://prnt.sc/feqmz2

[rdb (rdb)]

That (unless the debugger is incorrect) suggests again that something is being called on a nullptr GraphicsEngine.

It could be that something more fundamentally wrong is going on in your build; for example that the compiler settings (_DEBUG or NDEBUG setting, or MSVC version) doesn't match the one one used to produce the Panda build.

[ponyboy837 (ponyboy837)]

That's very possible. But i don't know what would trigger that kind of issue.

[ponyboy837 (ponyboy837)]

And that's because the compiling settings should match. (It's a odd life we have)

[rdb (rdb)]

Could this be a similar issue to https://bugs.launchpad.net/panda3d/+bug/1694353 ; due to improper reference counting?

[rdb (rdb)]

If you have a reproduction case that can be easily compiled and run by one of the developers, please reopen this bug on GitHub.

[Launchpad Janitor (janitor)]

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