Subj : Segmentation fault when using malloc with threads
To   : comp.programming.threads
From : Karthik007
Date : Sun Feb 27 2005 06:08 am


Hi!!

I am writing a client/server application for file transfer. The server is
a concurrent server implemented on threads concept. I have pasted some
code snippets from the server program.

main()
{

 pthread_t  srvThread[10];
 struct control data[10];
 int cliNum = 0;

  while(1) 
      {
          puts("\nServer Waiting.......\n");

	  recvmsg();
          sendmsg();
        
          if(userAuthenticate() == SUCCESS)
          {
             if(sock_fd == -1)
             {
	 		perror();
			continue;
	     }
             else
             {
                cliNum++;
                data[cliNum] = data[0];
                
                pthread_create(&srvThread[cliNum],NULL,handleRequest,(void
*)&data[cliNum]);

                
             } 
	   } 
       }
}


void *handleRequest(void *arg)
{

  
  struct control *info;
  
  info = (struct control *)malloc(sizeof(struct control));
  
  
  bzero(info, sizeof(struct control));
 
  info = (struct control *) arg;
  

  info->status = 0;
  pthread_detach(pthread_self());

   do
   {
       

   }while( );

  close(info->sock_fd);
  free(info);
  return NULL;
}


The problem is when i connect the server from a client it works fine and
when i  connect additional clients with "atleast one client already
connected" the program works fine, but when a client has connects and then
disconnects aafter which i try to connect a new client the malloc() call
fails giving a "Segmentation fault" error.

The system i am running this program is a P4 with 256MB RAM and the OS is
fedora core 2.

I request you kind help in solving this problem.

Thanking you in advance
Karthik

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