Crash on thread exit if image with TLS object with destructor is unloaded

[X512]

This is hrev56630.

Steps to reproduce:

1. Dynamically load image that creates TLS object with destructor.
2. Unload image.
3. Exit thread. TLS object destructor from unloaded image will be called and cause crash.

Reproduce code attached.

[jessicah]

I wonder if adding an implementation of __cxa_thread_exit that can call into runtime_loader directly, would be the right way to do this. Will require updating buildtools once an implementation has been added.

[waddlesplash]

We already have thread hooks that call TLS destructors: ​https://xref.landonf.org/source/xref/haiku/src/system/libroot/os/thread.c#170

So the real problem is that things are not called in the right order.

[X512]

No, real problem is that TLS destructors should be called at image unload, not thread exit if image containing TLS variable is unloaded.

[jessicah]

Hmm, so does that mean that ​https://cgit.haiku-os.org/haiku/tree/src/system/runtime_loader/elf.cpp#n773 isn't doing the right thing here, and we should be destroying the TLS block immediately?

[korli]

Sounds like ​https://sourceware.org/glibc/wiki/Destructor%20support%20for%20thread_local%20variables