Why close() system call returns bad status or -9 on Red Hat Enterprise Linux 5. 6 containg kernel 2.6.33.9-rt31.64.el5rt?

Issue

• Why close() system call returns bad status or -9 on Red Hat Enterprise Linux 5. 6 containg kernel 2.6.33.9-rt31.64.el5rt?
• Kernel 2.6.24.7-149.el5rt has been upgraded to 2.6.33.9-rt31.64.el5rt. After that, xinetd exited and it can't be used any more.
• Different behaviours has been observed on system built in RHEL5.6 with kernel 2.6.33.9-rt31.64.el5rt.

Example of code and its execution :

cat close.c 
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

int main()
{
  int fd;
  int first,second;

  if ( (fd = open("/proc/mounts", O_RDONLY)) != -1 ){
    printf("File descriptor : %d\n",fd);
    first=close(fd);
    perror("first");
    second=close(fd);
    perror("second");
    printf("first = %d\nsecond = %d\n",first,second);
  }
  else {
    printf("Unable to open file\n");
  }
}

close() syscall return bad status concerning bad file descriptor :

File descriptor : 3
first: Success
second: Illegal seek
first = 0
second = -9

Expected result :

File descriptor : 3
first: Success
second: Bad file descriptor
first = 0
second = -1

• This problem causes some applications to exit for bad reasons.