github.com/rakyll/go@v0.0.0-20170216000551-64c02460d703/src/runtime/testdata/testprogcgo/racesig.go (about)

     1  // Copyright 2016 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  // +build linux,amd64
     6  
     7  package main
     8  
     9  // Test that an external C thread that is calling malloc can be hit
    10  // with SIGCHLD signals. This used to fail when built with the race
    11  // detector, because in that case the signal handler would indirectly
    12  // call the C malloc function.
    13  
    14  /*
    15  #include <errno.h>
    16  #include <signal.h>
    17  #include <stdint.h>
    18  #include <stdio.h>
    19  #include <stdlib.h>
    20  #include <pthread.h>
    21  #include <sched.h>
    22  #include <unistd.h>
    23  
    24  #define ALLOCERS 100
    25  #define SIGNALERS 10
    26  
    27  static void* signalThread(void* p) {
    28  	pthread_t* pt = (pthread_t*)(p);
    29  	int i, j;
    30  
    31  	for (i = 0; i < 100; i++) {
    32  		for (j = 0; j < ALLOCERS; j++) {
    33  			if (pthread_kill(pt[j], SIGCHLD) < 0) {
    34  				return NULL;
    35  			}
    36  		}
    37  		usleep(1);
    38  	}
    39  	return NULL;
    40  }
    41  
    42  #define CALLS 100
    43  
    44  static void* mallocThread(void* p) {
    45  	int i;
    46  	void *a[CALLS];
    47  
    48  	for (i = 0; i < ALLOCERS; i++) {
    49  		sched_yield();
    50  	}
    51  	for (i = 0; i < CALLS; i++) {
    52  		a[i] = malloc(i);
    53  	}
    54  	for (i = 0; i < CALLS; i++) {
    55  		free(a[i]);
    56  	}
    57  	return NULL;
    58  }
    59  
    60  void runRaceSignalThread() {
    61  	int i;
    62  	pthread_t m[ALLOCERS];
    63  	pthread_t s[SIGNALERS];
    64  
    65  	for (i = 0; i < ALLOCERS; i++) {
    66  		pthread_create(&m[i], NULL, mallocThread, NULL);
    67  	}
    68  	for (i = 0; i < SIGNALERS; i++) {
    69  		pthread_create(&s[i], NULL, signalThread, &m[0]);
    70  	}
    71  	for (i = 0; i < SIGNALERS; i++) {
    72  		pthread_join(s[i], NULL);
    73  	}
    74  	for (i = 0; i < ALLOCERS; i++) {
    75  		pthread_join(m[i], NULL);
    76  	}
    77  }
    78  */
    79  import "C"
    80  
    81  import (
    82  	"fmt"
    83  	"os"
    84  	"time"
    85  )
    86  
    87  func init() {
    88  	register("CgoRaceSignal", CgoRaceSignal)
    89  }
    90  
    91  func CgoRaceSignal() {
    92  	// The failure symptom is that the program hangs because of a
    93  	// deadlock in malloc, so set an alarm.
    94  	go func() {
    95  		time.Sleep(5 * time.Second)
    96  		fmt.Println("Hung for 5 seconds")
    97  		os.Exit(1)
    98  	}()
    99  
   100  	C.runRaceSignalThread()
   101  	fmt.Println("OK")
   102  }