1// Copyright 2017 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5package main 6 7// This program hung when run under the C/C++ ThreadSanitizer. TSAN defers 8// asynchronous signals until the signaled thread calls into libc. The runtime's 9// sysmon goroutine idles itself using direct usleep syscalls, so it could 10// run for an arbitrarily long time without triggering the libc interceptors. 11// See https://golang.org/issue/18717. 12 13import ( 14 "os" 15 "os/signal" 16 "syscall" 17) 18 19/* 20#cgo CFLAGS: -g -fsanitize=thread 21#cgo LDFLAGS: -g -fsanitize=thread 22 23#include <signal.h> 24#include <stdio.h> 25#include <stdlib.h> 26#include <string.h> 27 28static void raise_usr2(int signo) { 29 raise(SIGUSR2); 30} 31 32static void register_handler(int signo) { 33 struct sigaction sa; 34 memset(&sa, 0, sizeof(sa)); 35 sigemptyset(&sa.sa_mask); 36 sa.sa_flags = SA_ONSTACK; 37 sa.sa_handler = raise_usr2; 38 39 if (sigaction(SIGUSR1, &sa, NULL) != 0) { 40 perror("failed to register SIGUSR1 handler"); 41 exit(EXIT_FAILURE); 42 } 43} 44*/ 45import "C" 46 47func main() { 48 ch := make(chan os.Signal, 1) 49 signal.Notify(ch, syscall.SIGUSR2) 50 51 C.register_handler(C.int(syscall.SIGUSR1)) 52 syscall.Kill(syscall.Getpid(), syscall.SIGUSR1) 53 54 <-ch 55} 56