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Source file src/runtime/testdata/testprogcgo/racesig.go

Documentation: runtime/testdata/testprogcgo

  // Copyright 2016 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  // +build linux,amd64
  
  package main
  
  // Test that an external C thread that is calling malloc can be hit
  // with SIGCHLD signals. This used to fail when built with the race
  // detector, because in that case the signal handler would indirectly
  // call the C malloc function.
  
  /*
  #include <errno.h>
  #include <signal.h>
  #include <stdint.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <pthread.h>
  #include <sched.h>
  #include <unistd.h>
  
  #define ALLOCERS 100
  #define SIGNALERS 10
  
  static void* signalThread(void* p) {
  	pthread_t* pt = (pthread_t*)(p);
  	int i, j;
  
  	for (i = 0; i < 100; i++) {
  		for (j = 0; j < ALLOCERS; j++) {
  			if (pthread_kill(pt[j], SIGCHLD) < 0) {
  				return NULL;
  			}
  		}
  		usleep(1);
  	}
  	return NULL;
  }
  
  #define CALLS 100
  
  static void* mallocThread(void* p) {
  	int i;
  	void *a[CALLS];
  
  	for (i = 0; i < ALLOCERS; i++) {
  		sched_yield();
  	}
  	for (i = 0; i < CALLS; i++) {
  		a[i] = malloc(i);
  	}
  	for (i = 0; i < CALLS; i++) {
  		free(a[i]);
  	}
  	return NULL;
  }
  
  void runRaceSignalThread() {
  	int i;
  	pthread_t m[ALLOCERS];
  	pthread_t s[SIGNALERS];
  
  	for (i = 0; i < ALLOCERS; i++) {
  		pthread_create(&m[i], NULL, mallocThread, NULL);
  	}
  	for (i = 0; i < SIGNALERS; i++) {
  		pthread_create(&s[i], NULL, signalThread, &m[0]);
  	}
  	for (i = 0; i < SIGNALERS; i++) {
  		pthread_join(s[i], NULL);
  	}
  	for (i = 0; i < ALLOCERS; i++) {
  		pthread_join(m[i], NULL);
  	}
  }
  */
  import "C"
  
  import (
  	"fmt"
  	"os"
  	"time"
  )
  
  func init() {
  	register("CgoRaceSignal", CgoRaceSignal)
  }
  
  func CgoRaceSignal() {
  	// The failure symptom is that the program hangs because of a
  	// deadlock in malloc, so set an alarm.
  	go func() {
  		time.Sleep(5 * time.Second)
  		fmt.Println("Hung for 5 seconds")
  		os.Exit(1)
  	}()
  
  	C.runRaceSignalThread()
  	fmt.Println("OK")
  }
  

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