[Apple Silicon] non-Go code set up signal handler without SA_ONSTACK flag

[st0pli]

macbookpro m2
The program occasionally crashes and reports the following error:

signal 16 received but handler not on signal stack
fatal error: non-Go code set up signal handler without SA_ONSTACK flag

go/src/syscall/zerrors_darwin_arm64.go
SIGURG = Signal(0x10)

go 1.20
go 1.23
All of these versions are available, but not on linux

I found the following description, I don't know if it works:

If a SIGPIPE signal is received, the Go program will invoke the special handling described above if the SIGPIPE is received on a Go thread. If the SIGPIPE is received on a non-Go thread the signal will be forwarded to the non-Go handler, if any; if there is none the default system handler will cause the program to terminate.

[st0pli]

This code is working.

package main

import (
	"github.com/mappu/miqt/qt"
	"os"
	"syscall"
)

/*
#include <stdint.h>
#include <stdio.h>

#ifdef __cplusplus
#include <csignal>
#else
#include <signal.h>
#endif

void Ignore(int sigNum);

void Ignore(int sigNum) {
    struct sigaction sa;
    sa.sa_handler = SIG_DFL;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags |= SA_ONSTACK;
    sigaction(sigNum, &sa, NULL);
}

*/
import "C"

func Ignore(sigNum syscall.Signal) {
	C.Ignore(C.int(sigNum))
}

func main() {
	qt.NewQApplication(os.Args)
        // your code
	Ignore(syscall.SIGURG)
	qt.QApplication_Exec()
}

[mappu]

I haven't tried MIQT on Apple Silicon before. I'm interested to hear about any problems.

I think Go uses the SIGURG signal itself, to switch between running goroutines. It should always be caught by Go's internal signal handler:

sigPreempt is the signal used for non-cooperative preemption.

We use SIGURG

• https://github.com/golang/go/blob/19e923182e590ae6568c2c714f20f32512aeb3e3/src/runtime/signal_unix.go#L43

Therefore if SIGURG was ignored, or if it was caught by another signal handler, then some goroutine functionality might not work fully.

[st0pli]

The problem has not been found yet, but there is no abnormal exit after doing this, and it continues to find

Update some code
sa.sa_handler = SIG_DFL;
sa.sa_flags |= SA_ONSTACK;