Unable to read from filedescriptor, program is killed

Question

I am trying to read a filedescriptor with read() but my program freezes there and after a while is Killed. Is there a timeout for reading filedescriptors or a good way to check why this happens? My program uses gadgetfs to read/write from/to USB in user space. Thanks! This is the code. It's a modified version of the usb.c samle (http://www.linux-usb.org/gadget/usb.c)

struct pollfd ep0_poll;
ep0_poll.fd = gadgetFS_FD;
ep0_poll.events = POLLIN | POLLOUT | POLLHUP;

while(){
                int nPoll = poll(&ep0_poll, 1, 250);    
            if(nPoll == 0)
                continue;

            if (nPoll < 0) {
                printf("poll failed");          
            }

            usb_gadgetfs_event  aoEvent [5];
            ssize_t nRead = read (ep0_poll.fd, &aoEvent, sizeof aoEvent);

            if (nRead < 0) {
                if (errno == EAGAIN) {
                    sleep (1);
                    continue;
                }
                printf("ep0 read after poll");
            }

                  ...

    }