mmap

Hi all, When tracking mmaps from LSM with the following hook: static int file_mmap(struct file *file, unsigned long reqprot, unsigned long prot, unsigned long flags, unsigned long addr, unsigned long addr_only); I often get: file = NULL flags = 0x0 (MAP_FILE) prot = 0x0 (PROT_NONE) I am wondering what is the use for mmap with MAP_FILE and PROT_NONE together ? Not sure how to interpret that ? -- Christophe