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 5 package 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 13 import ( 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 28 static void raise_usr2(int signo) { 29 raise(SIGUSR2); 30 } 31 32 static 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 */ 45 import "C" 46 47 func main() { 48 ch := make(chan os.Signal) 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
