FIXME: possible crash due to resched triggered by put_files_struct()

When parent process is exiting, the last put_files_struct() would try
to drop all files which triggers a resched(). In get_process_socket()
it will access the files tables of the process which is being exit,
and thus trigger the resched() in atomic context.

Signed-off-by: shenping.matt <[email protected]>