Rust runtime fails trying to create threads with requested stack size < TLS size

[kalenedrael]

Linking with certain external libraries can inflate the required amount of thread local storage to astronomical proportions. When the Rust runtime tries to create its threads, it requests a stack size independent of the TLS size, which can lead to pthread_create() failing with EINVAL when the stack size is smaller than the TLS size. This was apparently an issue for the Go runtime as well (http://sourceware.org/ml/libc-alpha/2012-06/msg00175.html).

A potential workaround is to add __static_tls_size (+ possibly a guard page) to the requested stack size, but it's arguably a bug in glibc that TLS comes out of the requested stack, instead of being added to it. This solution is also admittedly not very pleasing...

[kalenedrael]

I made a mistake. The workaround should actually be to add __pthread_get_minstack(&attr) to the requested size in src/rt/sync/rust_thread.cpp. It's still not very pleasing.

[luqmana]

This is the bug in glibc http://sourceware.org/bugzilla/show_bug.cgi?id=11787

[emberian]

Still relevant, but it's an upstream bug. Removing E-easy

[huonw]

Triage: we still call pthread_attr_setstacksize without adjusting for __pthread_get_minstack so I assume that the work-around hasn't been implemented, and the upstream bug is still open (and without activity for more than 3 months).

[huonw]

Triage: still a bug even with the pure Rust runtime.

#[feature(thread_local)];
#[allow(dead_code)];

#[cfg(crash)]
static SIZE: uint = 1 << 20; // 1 MB

#[cfg(not(crash))]
static SIZE: uint = 1 << 10; // 1 KB

#[thread_local]
static FOO: [u8, .. SIZE] = [0, .. SIZE];

fn main() {}

With --cfg crash it crashes with:

task '<unnamed>' failed at 'assertion failed: `(left == right) && (right == left)` (left: `22i32`, right: `0i32`)', /home/huon/rust/src/libstd/rt/thread.rs:211
failed at 'called `Option::unwrap()` on a `None` value', /home/huon/rust/src/libstd/option.rs:133

and without that --cfg it runs fine.

I'll attempt to fix it now.

[huonw]

(The above crash appears to not happen on Mac OSX; I'm on Linux.)

I opened #11284; but I don't think that work-around is complete enough to close this.

[huonw]

My patch caused people linking errors (__pthread_get_minstack is apparently not in all versions of glibc (works in 2.17, fails with 2.13), being a private function), so I'm reverting it in #11331.