racesig.go

     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  //go:build (linux && amd64) || (freebsd && amd64)
     6  // +build linux,amd64 freebsd,amd64
     7  
     8  package main
     9  
    10  // Test that an external C thread that is calling malloc can be hit
    11  // with SIGCHLD signals. This used to fail when built with the race
    12  // detector, because in that case the signal handler would indirectly
    13  // call the C malloc function.
    14  
    15  /*
    16  #include <errno.h>
    17  #include <signal.h>
    18  #include <stdint.h>
    19  #include <stdio.h>
    20  #include <stdlib.h>
    21  #include <pthread.h>
    22  #include <sched.h>
    23  #include <unistd.h>
    24  
    25  #define ALLOCERS 100
    26  #define SIGNALERS 10
    27  
    28  static void* signalThread(void* p) {
    29  	pthread_t* pt = (pthread_t*)(p);
    30  	int i, j;
    31  
    32  	for (i = 0; i < 100; i++) {
    33  		for (j = 0; j < ALLOCERS; j++) {
    34  			if (pthread_kill(pt[j], SIGCHLD) < 0) {
    35  				return NULL;
    36  			}
    37  		}
    38  		usleep(1);
    39  	}
    40  	return NULL;
    41  }
    42  
    43  #define CALLS 100
    44  
    45  static void* mallocThread(void* p) {
    46  	int i;
    47  	void *a[CALLS];
    48  
    49  	for (i = 0; i < ALLOCERS; i++) {
    50  		sched_yield();
    51  	}
    52  	for (i = 0; i < CALLS; i++) {
    53  		a[i] = malloc(i);
    54  	}
    55  	for (i = 0; i < CALLS; i++) {
    56  		free(a[i]);
    57  	}
    58  	return NULL;
    59  }
    60  
    61  void runRaceSignalThread() {
    62  	int i;
    63  	pthread_t m[ALLOCERS];
    64  	pthread_t s[SIGNALERS];
    65  
    66  	for (i = 0; i < ALLOCERS; i++) {
    67  		pthread_create(&m[i], NULL, mallocThread, NULL);
    68  	}
    69  	for (i = 0; i < SIGNALERS; i++) {
    70  		pthread_create(&s[i], NULL, signalThread, &m[0]);
    71  	}
    72  	for (i = 0; i < SIGNALERS; i++) {
    73  		pthread_join(s[i], NULL);
    74  	}
    75  	for (i = 0; i < ALLOCERS; i++) {
    76  		pthread_join(m[i], NULL);
    77  	}
    78  }
    79  */
    80  import "C"
    81  
    82  import (
    83  	"fmt"
    84  	"os"
    85  	"time"
    86  )
    87  
    88  func init() {
    89  	register("CgoRaceSignal", CgoRaceSignal)
    90  }
    91  
    92  func CgoRaceSignal() {
    93  	// The failure symptom is that the program hangs because of a
    94  	// deadlock in malloc, so set an alarm.
    95  	go func() {
    96  		time.Sleep(5 * time.Second)
    97  		fmt.Println("Hung for 5 seconds")
    98  		os.Exit(1)
    99  	}()
   100  
   101  	C.runRaceSignalThread()
   102  	fmt.Println("OK")
   103  }
   104
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