Kiran Pamnany

I tested the spectra diagnostics (which is what introduced the requirement for FFTW) with FFTW.jl built with MKL (by setting `JULIA_FFTW_PROVIDER=MKL` and building FFTW.jl). It runs fine and Lenka has...

Unreachable and illegal instruction from this code as well. I also put it in a file: ```julia function run() N = 800 for k = 1:10 @time begin count=0 iter...

Wow. And lol!

For this error: ``` /cache/build/default-amdci5-6/julialang/julia-master/src/stackwalk.c:1124:9: error: Passing non-rooted value as argument to function that may GC [julia.GCChecker] --   | jlbacktracet(ptls2->root_task);   | ^ ~~~~~~~~~~~~~~~~ ``` Do I have to `JL_GC_PUSH1(&ptls2->root_task)` and...

Also, I don't understand this? ``` /cache/build/default-amdci5-6/julialang/julia-master/src/stackwalk.c:1119:54: note: Argument value was derived global with untracked type. You may want to update the checker's type list --   | jl_safe_printf(" ---- Root...

We're experimenting with this to see if it's useful. As Nathan said, this is basically for use in `gdb`, i.e. all threads will be stopped, so poking into other threads'...

I added a comment warning that this is only intended for use when all threads are stopped (i.e. in `gdb`). I also removed it from exported functions for that reason....

 This profile? Had no `dl_iterate_phdr`... but yes, `sigprocmask`. Edit: ah, it was in the code we were looking at.

> I believe it is protecting us against the internal lock in `dl_iterate_phdr` from causing deadlocks for the process (since libunwind promises to be async-signal-safe). That sounds unavoidable then? @vchuravy's...

On reflection, I don't think that could happen. If we're walking the stack for an exception and an address from a shared object is on the stack, it should be...