std: detect stack overflows in TLS destructors on UNIX #131282
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Fixes rust-lang#111272. With rust-lang#127912 merged, we now have all the infrastructure in place to support stack overflow detection in TLS destructors. This was not possible before because the signal stack was freed in the thread main function, thus a SIGSEGV afterwards would immediately crash. And on platforms without native TLS, the guard page address was stored in an allocation freed in a TLS destructor, so would not be available. rust-lang#127912 introduced the `local_pointer` macro which allows storing a pointer-sized TLS variable without allocation and the `thread_cleanup` runtime function which is called after all other code managed by the Rust runtime. This PR simply moves the signal stack cleanup to the end of `thread_cleanup` and uses `local_pointer` to store every necessary variable. And so, everything run under the Rust runtime is now properly protected against stack overflows.
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Fixes #111272.
With #127912 merged, we now have all the infrastructure in place to support stack overflow detection in TLS destructors. This was not possible before because the signal stack was freed in the thread main function, thus a SIGSEGV afterwards would immediately crash. And on platforms without native TLS, the guard page address was stored in an allocation freed in a TLS destructor, so would not be available. #127912 introduced the
local_pointermacro which allows storing a pointer-sized TLS variable without allocation and thethread_cleanupruntime function which is called after all other code managed by the Rust runtime. This PR simply moves the signal stack cleanup to the end ofthread_cleanupand useslocal_pointerto store every necessary variable. And so, everything run under the Rust runtime is now properly protected against stack overflows.