Segfault while building the Rust toolchain with a toolchain that uses mimalloc

Nobody has claimed this yet.

So I'm trying to build a Rust toolchain with mimalloc that works here: https://github.com/rust-lang/rust/pull/62340 , such that we can use the Rust toolchain compiler benchmark suite to test whether it would be worth it switching to mimalloc from jemalloc.

I think I've managed so far to link mimalloc properly, and built a toolchain that's statically linked with it and uses it. When that toolchain is used to build another toolchain, after building a chunk of it, it segfaults with: signal: 11, SIGSEGV: invalid memory reference. Target is x86_64-unknown-linux-gnu , and I'm using the master branch of mimalloc, via the mimalloc-sys bindings, which are here: https://github.com/gnzlbg/mimallocator/tree/master/mimalloc-sys

I'm building mimalloc following the steps from this script: https://github.com/gnzlbg/mimallocator/blob/master/mimalloc-sys/build.rs

Start with the mimalloc-sys/build.rs steps and the Rust toolchain configuration described in the issue, targeting x86_64-unknown-linux-gnu. Reproduce the nested toolchain build and narrow down where the SIGSEGV occurs; done means the toolchain builds without the reported crash or the failure is isolated with actionable evidence.

Written by the indexing model from the issue text.