InterruptException not triggered by SIGINT when blocking background thread on 1.10

[simonbyrne]

In Julia 1.9, a SIGINT would reliably still trigger an InterruptExcpetion when a non-interactive thread was blocked by a ccall.

# try_csleep.jl
Base.exit_on_sigint(false)

@show Threads.nthreads()
println(getpid())
try
    wait(Threads.@spawn begin
         @show Threads.threadid()
         ccall(:sleep, Cuint, (Cuint,), 60)
     end)
catch e
    println("error $e")
    exit()
end
println("success")

On Julia 1.9.4:

├ julia -t 2  try_csleep.jl
Threads.nthreads() = 2
1125258
Threads.threadid() = 2
^Cerror InterruptException()

(also able to trigger it via kill -INT <procid>)

On Julia 1.10.0

├ julia -t 2  try_csleep.jl
Threads.nthreads() = 2
1125350
Threads.threadid() = 2
^C^C^C^C^C^C^C^CWARNING: Force throwing a SIGINT
error InterruptException()

(kill -INT <procid> does nothing)

Possibly related to #52291 (cc @Keno @vtjnash)

[Keno]

Possibly related to #52291 (cc @Keno @vtjnash)

Related in the sense that it's the same problem, but not in the sense that this predates the additional complications that prompted that issue.