Close for text file causing segmentation error and `glibc detected` under linux in C ++

I have a log class, this class contains a stream defined as: ofstream logfileand a mutex so that each time only one stream is written to the file (the program is multithreaded). A class is defined as:

#define LOG_NAME "log.txt"

using namespace std;

class Log
{
private:
    pthread_mutex_t mutex_write;
    ofstream logfile;

public:
    Log();
    ~Log();
    void Write (string txt);
};

Constructor:

Log::Log()
{
    pthread_mutex_init (&mutex_write,NULL);
    pthread_mutex_lock (&mutex_write);
    logfile.open(LOG_NAME, ios::out | ios::trunc);
    logfile << "Created log file named " << LOG_NAME << endl;
    pthread_mutex_unlock (&mutex_write);
}

Destructor:

Log::~Log()
{
    logfile << "Closing log file" << endl;
    pthread_mutex_lock (&mutex_write);
    logfile.close();
    pthread_mutex_unlock (&mutex_write);
    pthread_mutex_destroy (&mutex_write);
}

and

void Log::Write (string txt)
{
    pthread_mutex_lock (&mutex_write);
    logfile << txt << endl;
    pthread_mutex_unlock (&mutex_write);
}

At the time the destructor is called, it cannot execute the line logfile.close();because it says it is getting a segmentation error or it displays a message:

*** glibc detected *** corrupted double-linked list: 0x0000000000513eb0 ***
Abort

This does not always happen, it happens randomly in about 10% of cases. The program is multithreaded (under Linux).

Edit: usage example: (where logis a pointer to a class object log)

stringstream str;
str.str("");
str << "Ant " << i << " was created at place: (" << x << "," << y << ")";
log->Write (str.str());

or if the string contains only text

log->Write ("Created board entity");