From: "Huang, Ying" This patch fixes a bug of change_page_attr/change_page_attr_addr on Intel x86_64 CPU. After changing page attribute to be executable with these functions, the page remains un-executable on Intel x86_64 CPU. Because on Intel x86_64 CPU, only if the "NX" bits of all four level page tables are cleared, the corresponding page is executable (refer to section 4.13.2 of Intel 64 and IA-32 Architectures Software Developer's Manual). So, the bug is fixed through clearing the "NX" bit of PMD when splitting the huge PMD. Signed-off-by: Huang Ying Cc: Andi Kleen Signed-off-by: Andrew Morton --- arch/x86_64/mm/pageattr.c | 1 + 1 file changed, 1 insertion(+) diff -puN arch/x86_64/mm/pageattr.c~x86_64-nx-bit-handling-in-change_page_attr arch/x86_64/mm/pageattr.c --- a/arch/x86_64/mm/pageattr.c~x86_64-nx-bit-handling-in-change_page_attr +++ a/arch/x86_64/mm/pageattr.c @@ -184,6 +184,7 @@ __change_page_attr(unsigned long address split = split_large_page(address, prot, ref_prot2); if (!split) return -ENOMEM; + pgprot_val(ref_prot2) &= ~_PAGE_NX; set_pte(kpte, mk_pte(split, ref_prot2)); kpte_page = split; } _