Crash when using a multithreaded loop with BigFloat on macOS

[giordano]

I've been observing the this crash for a while on macOS with Julia v1.3+, including nightly, in CI of LombScargle.jl. Today I've been able to create a smallish self-contained code to reproduce it:

using LinearAlgebra, Base.Threads

function _generalised_lombscargle!(P, freqs, times, y, w, Y, YY, T)
    Threads.@threads for n in eachindex(freqs)
        ω = freqs[n] * 2 * pi
        # Find τ for current angular frequency
        C = zero(T)
	S = zero(T)
	CS = zero(T)
	CC = zero(T)
        for i in eachindex(times)
            W    = w[i]
            s, c = sincos(ω * times[i])
            CS  += W*c*s
            CC  += W*c*c
            C   += W*c
            S   += W*s
        end
        CS -= C*S
        SS  = 1 - CC - S*S
        CC -= C*C
        ωτ   = atan(2CS, CC - SS) / 2
        # Now we can compute the power
        YC_τ = zero(T)
	YS_τ = zero(T)
	CC_τ = zero(T)
        for i in eachindex(times)
            W     = w[i]
            s, c  = sincos(ω*times[i] - ωτ)
            YC_τ += W*y[i]*c
            YS_τ += W*y[i]*s
            CC_τ += W*c*c
        end
        # "C_τ" and "S_τ" are computed following equation (7) of Press &
        # Rybicki, this formula simply comes from angle difference trigonometric
        # identities.
        sin_ωτ, cos_ωτ = sincos(ωτ)
        C_τ    = C*cos_ωτ + S*sin_ωτ
        S_τ    = S*cos_ωτ - C*sin_ωτ
        YC_τ  -= Y*C_τ
        YS_τ  -= Y*S_τ
        SS_τ   = 1 - CC_τ - S_τ*S_τ
        CC_τ  -= C_τ*C_τ
        P[n] = (abs2(YC_τ)/CC_τ + abs2(YS_τ)/SS_τ)/YY
    end
    return P
end

times = 1:11
signal = big.(sin.(times))
w = fill!(similar(signal), one(eltype(signal))) / length(signal)
frequencies = 0.01:0.02:2.75
T = eltype(signal)
P = Vector{T}(undef, length(frequencies))
y = signal .- w ⋅ signal
Y = w ⋅ y
YY  = w ⋅ (y .^ 2) - Y * Y

_generalised_lombscargle!(P, frequencies, times, y, w, Y, YY, T)

When I run it on macOS with 2+ threads I get

julia(1539,0x700001a0e000) malloc: *** error for object 0x7f8eebd00520: pointer being realloc'd was not allocated
julia(1539,0x700001a0e000) malloc: *** set a breakpoint in malloc_error_break to debug

signal (6): Abort trap: 6
in expression starting at /Users/mose/foo.jl:59
__pthread_kill at /usr/lib/system/libsystem_kernel.dylib (unknown line)
Allocations: 1718565 (Pool: 1718182; Big: 383); GC: 2
Abort trap: 6

My understanding is that the nested for loops are the problem, when I comment them the code doesn't crash. I may be doing something silly, I wrote this code more than 2 years ago, but it has been working since then. It doesn't crash with Julia v1.2- nor any other operating system nor when using a single thread.

[mcabbott]

Can confirm this happens on my macs. Sometimes with a longer error message:

julia> _generalised_lombscargle!(P, frequencies, times, y, w, Y, YY, T)
julia(7335,0x7000103a5000) malloc: *** error for object 0x7f9fe130b8a0: pointer being realloc'd was not allocated
*** set a breakpoint in malloc_error_break to debug
julia(7335,0x7fff9bc69380) malloc: *** error for object 0x7f9fdbd01e60: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug

signal (6): Abort trap: 6
signal (6): Abort trap: 6
n expression starting at REPL[20]:1
in expression starting at REPL[20]:1
julia(7335,0x700011bae000) malloc: *** error for object 0x7f9fe132bee0: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug
__pthread_kill at /usr/lib/system/libsystem_kernel.dylib (unknown line)
julia(7335,0x7000103a5000) malloc: *** error for object 0x7f9fe132bad8: incorrect checksum for freed object - object was probably modified after being freed.
*** set a breakpoint in malloc_error_break to debug
Allocations: 16516003 (Poolllocations: 16516003 (Pool: 16511892; Big: 4111); GC: 20
in expression starting at REPL[20]:1
__pthread_kill at /usr/lib/system/libsystem_kernel.dylib (unknown line)
Allocations: 16516003 (Pool: 16511892; Big: 4111); GC: 20
Abort trap: 6

[mcabbott]

Appears to be fixed by #36776