Hi, We can use mprotect to set read only or read/write. mprotect_fixup() vma_set_page_prot() vm_pgprot_modify() vm_get_page_prot() protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)] The following code shows that prots from __P001(PROT_READ) and __P010(PROT_WRITE) are the same, so how does it distinguish read only or read/write from mprotect? pgprot_t protection_map[16] = { __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 }; #define __P001 PAGE_READONLY #define __P010 PAGE_COPY #define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER | \ _PAGE_ACCESSED | _PAGE_NX) #define PAGE_COPY_NOEXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | \ _PAGE_ACCESSED | _PAGE_NX) #define PAGE_COPY PAGE_COPY_NOEXEC Thanks, Xishi Qiu -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>