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问题描述
我正在尝试使用pthreads进行ebola模拟.直到信号灯部分，一切都工作正常.编译代码时出现此错误:
*** Error in `./ebola_serial': double free or corruption (out): 0x00007f49700008c0 ***
*** Error in `======= Backtrace: =========
/lib64/libc.so.6(+0x7238e)[0x7f49868f038e]
./ebola_serial/lib64/libc.so.6(+0x7a0c8)[0x7f49868f80c8]
': /lib64/libc.so.6(cfree+0x48)[0x7f49868fb798]
double free or corruption (out)/lib64/libc.so.6(fclose+0x113)[0x7f49868e6473]
./ebola_serial[0x401717]
/lib64/libpthread.so.0(+0x75bd)[0x7f4986c395bd]
: 0x/lib64/libc.so.6(clone+0x6d)[0x7f498697562d]
======= Memory map: ========
00007f49700008c000400000-00402000 r-xp 00000000 08:01 802698 /home/name/Desktop/try ca/ebola_serial
00601000-00602000 r--p 00001000 08:01 802698 /home/name/Desktop/try ca/ebola_serial
00602000-00603000 rw-p 00002000 08:01 802698 /home/name/Desktop/try ca/ebola_serial
00603000-009d3000 rw-p 00000000 00:00 0
01b96000-01bb7000 rw-p 00000000 00:00 0 [heap]
7f4970000000-7f4970021000 rw-p 00000000 00:00 0
7f4970021000-7f4974000000 ---p 00000000 00:00 0
7f4978000000-7f4978021000 rw-p 00000000 00:00 0
7f4978021000-7f497c000000 ---p 00000000 00:00 0
7f497c000000-7f497c021000 rw-p 00000000 00:00 0
7f497c021000-7f4980000000 ---p 00000000 00:00 0
7f4980000000-7f4980021000 rw-p 00000000 00:00 0
7f4980021000-7f4984000000 ---p 00000000 00:00 0
7f4984663000-7f4984679000 r-xp 00000000 08:01 131531 /usr/lib64/libgcc_s-4.9.2.so.1
7f4984679000-7f4984878000 ---p 00016000 08:01 131531 /usr/lib64/libgcc_s-4.9.2.so.1
7f4984878000-7f4984879000 r--p 00015000 08:01 131531 /usr/lib64/libgcc_s-4.9.2.so.1
7f4984879000-7f498487a000 rw-p 00016000 08:01 131531 /usr/lib64/libgcc_s-4.9.2.so.1
7f498487a000-7f498487b000 ---p 00000000 00:00 0
7f498487b000-7f498507b000 rw-p 00000000 00:00 0 [stack:7376]
7f498507b000-7f498507c000 ---p 00000000 00:00 0
7f498507c000-7f498587c000 rw-p 00000000 00:00 0
7f498587c000-7f498587d000 ---p 00000000 00:00 0
7f498587d000-7f498607d000 rw-p 00000000 00:00 0 [stack:7374]
7f498607d000-7f498607e000 ---p 00000000 00:00 0
7f498607e000-7f498687e000 rw-p 00000000 00:00 0 [stack:7373]
7f498687e000-7f4986a28000 r-xp 00000000 08:01 130947 /usr/lib64/libc-2.20.so
7f4986a28000-7f4986c28000 ---p 001aa000 08:01 130947 /usr/lib64/libc-2.20.so
7f4986c28000-7f4986c2c000 r--p 001aa000 08:01 130947 /usr/lib64/libc-2.20.so
7f4986c2c000-7f4986c2e000 rw-p 001ae000 08:01 130947 /usr/lib64/libc-2.20.so
7f4986c2e000-7f4986c32000 rw-p 00000000 00:00 0
7f4986c32000-7f4986c49000 r-xp 00000000 08:01 130973 /usr/lib64/libpthread-2.20.so
7f4986c49000-7f4986e48000 ---p 00017000 08:01 130973 /usr/lib64/libpthread-2.20.so
7f4986e48000-7f4986e49000 r--p 00016000 08:01 130973 /usr/lib64/libpthread-2.20.so
7f4986e49000-7f4986e4a000 rw-p 00017000 08:01 130973 /usr/lib64/libpthread-2.20.so
7f4986e4a000-7f4986e4e000 rw-p 00000000 00:00 0
7f4986e4e000-7f4986f53000 r-xp 00000000 08:01 130955 /usr/lib64/libm-2.20.so
7f4986f53000-7f4987152000 ---p 00105000 08:01 130955 /usr/lib64/libm-2.20.so
7f4987152000-7f4987153000 r--p 00104000 08:01 130955 /usr/lib64/libm-2.20.so
7f4987153000-7f4987154000 rw-p 00105000 08:01 130955 /usr/lib64/libm-2.20.so
7f4987154000-7f4987174000 r-xp 00000000 08:01 130940 /usr/lib64/ld-2.20.so
7f4987353000-7f4987356000 rw-p 00000000 00:00 0
7f498736d000-7f4987373000 rw-p 00000000 00:00 0
7f4987373000-7f4987374000 r--p 0001f000 08:01 130940 /usr/lib64/ld-2.20.so
7f4987374000-7f4987376000 rw-p 00020000 08:01 130940 /usr/lib64/ld-2.20.so
7ffce31e3000-7ffce3205000 rw-p 00000000 00:00 0 [stack]
7ffce320d000-7ffce320f000 r--p 00000000 00:00 0 [vvar]
7ffce320f000-7ffce3211000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
Aborted
这是我的代码:
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>
#include "timer.h"
#define NUMROW 1000
#define NUMCOL 1000
#define NUMCOMP 1000000
#define GEN 400
#define THREAD_COUNT 4
FILE *fp;
char buffer[32];
int map[1000][1000];
int neighbours[8];
int nextGen;
double chance;
int tInfection = 0;
int tHealthy = 0;
int tDead = 0;
int tRecovered = 0;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
sem_t semaphores[THREAD_COUNT];
int barrCount1,
barrCount2, totalDead, totalHealthy, totalInfection, totalRecovered, p;
pthread_mutex_t barrier_mutex;
void* mythread_func(void* rank)
{
long my_rank = (long) rank;
long i, j;
long my_row = NUMROW / THREAD_COUNT;
long my_col = my_row;
long my_first_i = my_row * my_rank;
long my_last_i = my_first_i + my_row - 1;
for (i = my_first_i; i < my_last_i; i++)
{
for (j = my_first_i; j < my_last_i; j++)
{
map[i][j] = 0;
}
}
int inf;
//infecting 5 random people
for (inf = 0; inf < 1; inf++)
{
double rand1 = floor(rand() % ((my_last_i + 1 - my_first_i) + my_first_i));
double rand2 = floor(rand() % ((my_last_i + 1 - my_first_i) + my_first_i));
int randFin1 = (int) rand1;
int randFin2 = (int) rand2;
map[randFin1][randFin2] = 1;
}
int k = 0;
long dest = (my_rank + 1) % THREAD_COUNT;
long genCount;
//loops of generation
for (genCount = 0; genCount < GEN; genCount++)
{
//mutex barrier---------------------------
pthread_mutex_lock(&barrier_mutex);
barrCount1++;
pthread_mutex_unlock(&barrier_mutex);
while (barrCount1 < THREAD_COUNT)
;
//----------------------------------------
//looping through columns and rows
for (i = my_first_i; i < my_last_i; i++)
{
for (j = my_first_i; j < my_last_i; j++)
{
nextGen = 1;
//left neigbour
neighbours[0] = map[(i + NUMROW - 1) % NUMROW][j];
//right neighbour
neighbours[1] = map[(i + NUMROW + 1) % NUMROW][j];
//top neighbour
neighbours[2] = map[i][(j + NUMROW - 1) % NUMROW];
//bottom neigbour
neighbours[3] = map[i][(j + NUMROW + 1) % NUMROW];
//bottom left neighbour
neighbours[4] =
map[(i + NUMROW - 1) % NUMROW][(j + NUMROW + 1) % NUMROW];
//bottom right neighbour
neighbours[5] =
map[(i + NUMROW + 1) % NUMROW][(j + NUMROW + 1) % NUMROW];
//top left neighbour
neighbours[6] =
map[(i + NUMROW - 1) % NUMROW][(j + NUMROW - 1) % NUMROW];
//top right neigbour
neighbours[7] =
map[(i + NUMROW + 1) % NUMROW][(j + NUMROW - 1) % NUMROW];
int infections = 0;
int dead = 0;
for (p = 0; p < 8; p++)
{
if (neighbours[p] == 1)
{
infections++;
}
if (neighbours[p] == 2)
{
dead++;
}
}
if (infections > 0 && map[i][j] == 0)
{
chance = 20.0;
if (floor(rand() % 101) < chance)
{
//Person is infected
tInfection++;
tHealthy--;
map[i][j] = 1;
nextGen = 0;
} //end of infections if statement
} //end of chancing life
if (map[i][j] == 1 && nextGen)
{
chance = 10.0;
if (floor(rand() % 101) < chance)
{
//Person is dead
tDead++;
tHealthy--;
map[i][j] = 2;
}
}
if (map[i][j] == 1 && nextGen)
{
chance = 0.5;
if (floor(rand() % 101) < chance)
{
tRecovered++;
tDead--;
map[i][j] = 3;
}
}
}
}
}
pthread_mutex_lock(&mutex);
totalHealthy += tHealthy;
totalDead += tDead;
totalInfection += tInfection;
totalRecovered += tRecovered;
pthread_mutex_unlock(&mutex);
//mutex barrier---------------------------
pthread_mutex_lock(&barrier_mutex);
barrCount2++;
pthread_mutex_unlock(&barrier_mutex);
while (barrCount2 < THREAD_COUNT)
;
//----------------------------------------
printf(
"-------------------------------------------------\nThread %ld numbers:\nHealthy: %d\nDead: %d\nInfected: %d\nRecovered: %d\n",
my_rank, totalHealthy, totalDead, totalInfection, totalRecovered);
//every 50 generations create file with results
if (genCount % 50 == 0)
{
//incrementing file name
sem_post(&semaphores[dest]);
sem_wait(&semaphores[my_rank]);
snprintf(buffer, sizeof(char) * 32, "file%i.dat", k);
//open the file
fp = fopen(buffer, "r+");
if (fp == NULL )
{
printf("I couldn't open file for writing.\n");
exit(0);
}
int loop1, loop2;
//outputting the array into the file
for (loop1 = my_first_i; loop1 < my_last_i; loop1++)
{
for (loop2 = my_first_i; loop2 < my_last_i; loop2++)
{
fprintf(fp, "%d\t", map[loop1][loop2]);
}
}
//close the file
fclose(fp);
k++;
}
return NULL ;
}
int main()
{
//int map[1000][1000];
//neighbours
int totalHealthy = 0;
int totalInfection = 0;
int totalDead = 0;
int totalRecovered = 0;
double chance = 20.0;
double start, finish, elapsed;
int i, j, g, inf;
int k = 0;
//--------------Seed For Random Numbers-----------
time_t t;
/* Inititializes random number generator*/
srand((unsigned) time(&t));
//------------------------------------------------
printf("Ebola spreading...\n");
//start timer------------------
GET_TIME(start);
//-----------------------------
//Thread code----------------------------------------------------------------------
long thread;
int semCount;
for (semCount = 0; semCount < THREAD_COUNT; semCount++)
{
sem_init(&semaphores[semCount], 0, 1);
}
pthread_t *mythread_handle;
mythread_handle = malloc(THREAD_COUNT * sizeof(pthread_t));
for (thread = 0; thread < THREAD_COUNT; thread++)
{
pthread_create(&mythread_handle[thread], NULL, mythread_func,
(void *) thread);
}
for (thread = 0; thread < THREAD_COUNT; thread++)
{
pthread_join(mythread_handle[thread], NULL );
}
pthread_mutex_destroy(&mutex);
//----------------------------------------------------------------------------------
//stop timer------------
GET_TIME(finish);
elapsed = finish - start;
free(mythread_handle);
printf("Time elapsed: %e seconds\n", elapsed);
return 0;
}
这是timer.h文件:
#ifndef _TIMER_H_
#define _TIMER_H_
#include <sys/time.h>
/* The argument now should be a double (not a pointer to a double) */
#define GET_TIME(now) { \
struct timeval t; \
gettimeofday(&t, NULL); \
now = t.tv_sec + t.tv_usec/1000000.0; \
}
#endif
任何帮助将不胜感激.谢谢
解决方案
* fp是全局变量，因此每个therad将使用fopen对其进行初始化，并在完成工作后尝试将其关闭. * fp在线程之间共享(不应共享)，因此退出前的每个线程都会尝试关闭* fp中存储的文件句柄，并且当多个线程试图关闭已被另一个线程关闭的文件句柄时，就会出现double free. >
必须将* fp放在功能块中以使其在每个线程中都为本地，或者在* fp声明之前添加__thread以使其在每个线程实例中都为本地. __thread FILE * fp;
I'm trying to do a ebola simulation using pthreads. Everything worked just fine up to the semaphor part.I'm getting this error while compiling code:
*** Error in `./ebola_serial': double free or corruption (out): 0x00007f49700008c0 ***
*** Error in `======= Backtrace: =========
/lib64/libc.so.6(+0x7238e)[0x7f49868f038e]
./ebola_serial/lib64/libc.so.6(+0x7a0c8)[0x7f49868f80c8]
': /lib64/libc.so.6(cfree+0x48)[0x7f49868fb798]
double free or corruption (out)/lib64/libc.so.6(fclose+0x113)[0x7f49868e6473]
./ebola_serial[0x401717]
/lib64/libpthread.so.0(+0x75bd)[0x7f4986c395bd]
: 0x/lib64/libc.so.6(clone+0x6d)[0x7f498697562d]
======= Memory map: ========
00007f49700008c000400000-00402000 r-xp 00000000 08:01 802698 /home/name/Desktop/try ca/ebola_serial
00601000-00602000 r--p 00001000 08:01 802698 /home/name/Desktop/try ca/ebola_serial
00602000-00603000 rw-p 00002000 08:01 802698 /home/name/Desktop/try ca/ebola_serial
00603000-009d3000 rw-p 00000000 00:00 0
01b96000-01bb7000 rw-p 00000000 00:00 0 [heap]
7f4970000000-7f4970021000 rw-p 00000000 00:00 0
7f4970021000-7f4974000000 ---p 00000000 00:00 0
7f4978000000-7f4978021000 rw-p 00000000 00:00 0
7f4978021000-7f497c000000 ---p 00000000 00:00 0
7f497c000000-7f497c021000 rw-p 00000000 00:00 0
7f497c021000-7f4980000000 ---p 00000000 00:00 0
7f4980000000-7f4980021000 rw-p 00000000 00:00 0
7f4980021000-7f4984000000 ---p 00000000 00:00 0
7f4984663000-7f4984679000 r-xp 00000000 08:01 131531 /usr/lib64/libgcc_s-4.9.2.so.1
7f4984679000-7f4984878000 ---p 00016000 08:01 131531 /usr/lib64/libgcc_s-4.9.2.so.1
7f4984878000-7f4984879000 r--p 00015000 08:01 131531 /usr/lib64/libgcc_s-4.9.2.so.1
7f4984879000-7f498487a000 rw-p 00016000 08:01 131531 /usr/lib64/libgcc_s-4.9.2.so.1
7f498487a000-7f498487b000 ---p 00000000 00:00 0
7f498487b000-7f498507b000 rw-p 00000000 00:00 0 [stack:7376]
7f498507b000-7f498507c000 ---p 00000000 00:00 0
7f498507c000-7f498587c000 rw-p 00000000 00:00 0
7f498587c000-7f498587d000 ---p 00000000 00:00 0
7f498587d000-7f498607d000 rw-p 00000000 00:00 0 [stack:7374]
7f498607d000-7f498607e000 ---p 00000000 00:00 0
7f498607e000-7f498687e000 rw-p 00000000 00:00 0 [stack:7373]
7f498687e000-7f4986a28000 r-xp 00000000 08:01 130947 /usr/lib64/libc-2.20.so
7f4986a28000-7f4986c28000 ---p 001aa000 08:01 130947 /usr/lib64/libc-2.20.so
7f4986c28000-7f4986c2c000 r--p 001aa000 08:01 130947 /usr/lib64/libc-2.20.so
7f4986c2c000-7f4986c2e000 rw-p 001ae000 08:01 130947 /usr/lib64/libc-2.20.so
7f4986c2e000-7f4986c32000 rw-p 00000000 00:00 0
7f4986c32000-7f4986c49000 r-xp 00000000 08:01 130973 /usr/lib64/libpthread-2.20.so
7f4986c49000-7f4986e48000 ---p 00017000 08:01 130973 /usr/lib64/libpthread-2.20.so
7f4986e48000-7f4986e49000 r--p 00016000 08:01 130973 /usr/lib64/libpthread-2.20.so
7f4986e49000-7f4986e4a000 rw-p 00017000 08:01 130973 /usr/lib64/libpthread-2.20.so
7f4986e4a000-7f4986e4e000 rw-p 00000000 00:00 0
7f4986e4e000-7f4986f53000 r-xp 00000000 08:01 130955 /usr/lib64/libm-2.20.so
7f4986f53000-7f4987152000 ---p 00105000 08:01 130955 /usr/lib64/libm-2.20.so
7f4987152000-7f4987153000 r--p 00104000 08:01 130955 /usr/lib64/libm-2.20.so
7f4987153000-7f4987154000 rw-p 00105000 08:01 130955 /usr/lib64/libm-2.20.so
7f4987154000-7f4987174000 r-xp 00000000 08:01 130940 /usr/lib64/ld-2.20.so
7f4987353000-7f4987356000 rw-p 00000000 00:00 0
7f498736d000-7f4987373000 rw-p 00000000 00:00 0
7f4987373000-7f4987374000 r--p 0001f000 08:01 130940 /usr/lib64/ld-2.20.so
7f4987374000-7f4987376000 rw-p 00020000 08:01 130940 /usr/lib64/ld-2.20.so
7ffce31e3000-7ffce3205000 rw-p 00000000 00:00 0 [stack]
7ffce320d000-7ffce320f000 r--p 00000000 00:00 0 [vvar]
7ffce320f000-7ffce3211000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
Aborted
This is my code:
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>
#include "timer.h"
#define NUMROW 1000
#define NUMCOL 1000
#define NUMCOMP 1000000
#define GEN 400
#define THREAD_COUNT 4
FILE *fp;
char buffer[32];
int map[1000][1000];
int neighbours[8];
int nextGen;
double chance;
int tInfection = 0;
int tHealthy = 0;
int tDead = 0;
int tRecovered = 0;
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
sem_t semaphores[THREAD_COUNT];
int barrCount1,
barrCount2, totalDead, totalHealthy, totalInfection, totalRecovered, p;
pthread_mutex_t barrier_mutex;
void* mythread_func(void* rank)
{
long my_rank = (long) rank;
long i, j;
long my_row = NUMROW / THREAD_COUNT;
long my_col = my_row;
long my_first_i = my_row * my_rank;
long my_last_i = my_first_i + my_row - 1;
for (i = my_first_i; i < my_last_i; i++)
{
for (j = my_first_i; j < my_last_i; j++)
{
map[i][j] = 0;
}
}
int inf;
//infecting 5 random people
for (inf = 0; inf < 1; inf++)
{
double rand1 = floor(rand() % ((my_last_i + 1 - my_first_i) + my_first_i));
double rand2 = floor(rand() % ((my_last_i + 1 - my_first_i) + my_first_i));
int randFin1 = (int) rand1;
int randFin2 = (int) rand2;
map[randFin1][randFin2] = 1;
}
int k = 0;
long dest = (my_rank + 1) % THREAD_COUNT;
long genCount;
//loops of generation
for (genCount = 0; genCount < GEN; genCount++)
{
//mutex barrier---------------------------
pthread_mutex_lock(&barrier_mutex);
barrCount1++;
pthread_mutex_unlock(&barrier_mutex);
while (barrCount1 < THREAD_COUNT)
;
//----------------------------------------
//looping through columns and rows
for (i = my_first_i; i < my_last_i; i++)
{
for (j = my_first_i; j < my_last_i; j++)
{
nextGen = 1;
//left neigbour
neighbours[0] = map[(i + NUMROW - 1) % NUMROW][j];
//right neighbour
neighbours[1] = map[(i + NUMROW + 1) % NUMROW][j];
//top neighbour
neighbours[2] = map[i][(j + NUMROW - 1) % NUMROW];
//bottom neigbour
neighbours[3] = map[i][(j + NUMROW + 1) % NUMROW];
//bottom left neighbour
neighbours[4] =
map[(i + NUMROW - 1) % NUMROW][(j + NUMROW + 1) % NUMROW];
//bottom right neighbour
neighbours[5] =
map[(i + NUMROW + 1) % NUMROW][(j + NUMROW + 1) % NUMROW];
//top left neighbour
neighbours[6] =
map[(i + NUMROW - 1) % NUMROW][(j + NUMROW - 1) % NUMROW];
//top right neigbour
neighbours[7] =
map[(i + NUMROW + 1) % NUMROW][(j + NUMROW - 1) % NUMROW];
int infections = 0;
int dead = 0;
for (p = 0; p < 8; p++)
{
if (neighbours[p] == 1)
{
infections++;
}
if (neighbours[p] == 2)
{
dead++;
}
}
if (infections > 0 && map[i][j] == 0)
{
chance = 20.0;
if (floor(rand() % 101) < chance)
{
//Person is infected
tInfection++;
tHealthy--;
map[i][j] = 1;
nextGen = 0;
} //end of infections if statement
} //end of chancing life
if (map[i][j] == 1 && nextGen)
{
chance = 10.0;
if (floor(rand() % 101) < chance)
{
//Person is dead
tDead++;
tHealthy--;
map[i][j] = 2;
}
}
if (map[i][j] == 1 && nextGen)
{
chance = 0.5;
if (floor(rand() % 101) < chance)
{
tRecovered++;
tDead--;
map[i][j] = 3;
}
}
}
}
}
pthread_mutex_lock(&mutex);
totalHealthy += tHealthy;
totalDead += tDead;
totalInfection += tInfection;
totalRecovered += tRecovered;
pthread_mutex_unlock(&mutex);
//mutex barrier---------------------------
pthread_mutex_lock(&barrier_mutex);
barrCount2++;
pthread_mutex_unlock(&barrier_mutex);
while (barrCount2 < THREAD_COUNT)
;
//----------------------------------------
printf(
"-------------------------------------------------\nThread %ld numbers:\nHealthy: %d\nDead: %d\nInfected: %d\nRecovered: %d\n",
my_rank, totalHealthy, totalDead, totalInfection, totalRecovered);
//every 50 generations create file with results
if (genCount % 50 == 0)
{
//incrementing file name
sem_post(&semaphores[dest]);
sem_wait(&semaphores[my_rank]);
snprintf(buffer, sizeof(char) * 32, "file%i.dat", k);
//open the file
fp = fopen(buffer, "r+");
if (fp == NULL )
{
printf("I couldn't open file for writing.\n");
exit(0);
}
int loop1, loop2;
//outputting the array into the file
for (loop1 = my_first_i; loop1 < my_last_i; loop1++)
{
for (loop2 = my_first_i; loop2 < my_last_i; loop2++)
{
fprintf(fp, "%d\t", map[loop1][loop2]);
}
}
//close the file
fclose(fp);
k++;
}
return NULL ;
}
int main()
{
//int map[1000][1000];
//neighbours
int totalHealthy = 0;
int totalInfection = 0;
int totalDead = 0;
int totalRecovered = 0;
double chance = 20.0;
double start, finish, elapsed;
int i, j, g, inf;
int k = 0;
//--------------Seed For Random Numbers-----------
time_t t;
/* Inititializes random number generator*/
srand((unsigned) time(&t));
//------------------------------------------------
printf("Ebola spreading...\n");
//start timer------------------
GET_TIME(start);
//-----------------------------
//Thread code----------------------------------------------------------------------
long thread;
int semCount;
for (semCount = 0; semCount < THREAD_COUNT; semCount++)
{
sem_init(&semaphores[semCount], 0, 1);
}
pthread_t *mythread_handle;
mythread_handle = malloc(THREAD_COUNT * sizeof(pthread_t));
for (thread = 0; thread < THREAD_COUNT; thread++)
{
pthread_create(&mythread_handle[thread], NULL, mythread_func,
(void *) thread);
}
for (thread = 0; thread < THREAD_COUNT; thread++)
{
pthread_join(mythread_handle[thread], NULL );
}
pthread_mutex_destroy(&mutex);
//----------------------------------------------------------------------------------
//stop timer------------
GET_TIME(finish);
elapsed = finish - start;
free(mythread_handle);
printf("Time elapsed: %e seconds\n", elapsed);
return 0;
}
Here is timer.h file:
#ifndef _TIMER_H_
#define _TIMER_H_
#include <sys/time.h>
/* The argument now should be a double (not a pointer to a double) */
#define GET_TIME(now) { \
struct timeval t; \
gettimeofday(&t, NULL); \
now = t.tv_sec + t.tv_usec/1000000.0; \
}
#endif
Any help would be appreciated. Thanks
解决方案
The *fp is a global variable, so each therad will initialize it with fopen and after finished working try to close it. the *fp is shared between threads (which should not be) so each thread before exiting tries to close the file handle stored in *fp and the double free occurs when multiple threads tries to close file handle which closed already by another thread.
You have to put *fp inside function block to make it local to each thread or add __thread before *fp declaration to make it local for each thread instance. __thread FILE * fp;
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