socket close problem

first my os is linux 2.6 kernel. i use two threads in my network code, one for read(), the other for write(). but the problem is, when the read thread is in the read() on fd1 and at this time clock interrupt then schedule happened(perhaps the read is copying data from kernel to user's buffer at this moment,but not finished), now the write tread is runing, and for some case it close fd1, then what will happen? thanks!