From: Pekka Enberg This adds special handling for revoked memory mappings. We want to raise SIGBUS when accessing revoked mappings and return ENODEV when trying to remap with mmap(2). Cc: Alan Cox Cc: Al Viro Cc: Christoph Hellwig Signed-off-by: Pekka Enberg --- include/linux/mm.h | 1 + mm/memory.c | 3 +++ mm/mmap.c | 12 ++++++++---- 3 files changed, 12 insertions(+), 4 deletions(-) Index: 2.6/include/linux/mm.h =================================================================== --- 2.6.orig/include/linux/mm.h 2007-10-26 15:24:28.000000000 +0300 +++ 2.6/include/linux/mm.h 2007-10-26 15:24:44.000000000 +0300 @@ -105,6 +105,7 @@ #define VM_INSERTPAGE 0x02000000 /* The #define VM_ALWAYSDUMP 0x04000000 /* Always include in core dumps */ #define VM_CAN_NONLINEAR 0x08000000 /* Has ->fault & does nonlinear pages */ +#define VM_REVOKED 0x10000000 /* Mapping has been revoked */ #ifndef VM_STACK_DEFAULT_FLAGS /* arch can override this */ #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS Index: 2.6/mm/memory.c =================================================================== --- 2.6.orig/mm/memory.c 2007-10-26 15:24:28.000000000 +0300 +++ 2.6/mm/memory.c 2007-10-26 15:24:44.000000000 +0300 @@ -2530,6 +2530,9 @@ int handle_mm_fault(struct mm_struct *mm if (unlikely(is_vm_hugetlb_page(vma))) return hugetlb_fault(mm, vma, address, write_access); + if (unlikely(vma->vm_flags & VM_REVOKED)) + return VM_FAULT_SIGBUS; + pgd = pgd_offset(mm, address); pud = pud_alloc(mm, pgd, address); if (!pud) Index: 2.6/mm/mmap.c =================================================================== --- 2.6.orig/mm/mmap.c 2007-10-26 15:24:28.000000000 +0300 +++ 2.6/mm/mmap.c 2007-10-26 15:24:44.000000000 +0300 @@ -1078,10 +1078,14 @@ unsigned long charged = 0; error = -ENOMEM; munmap_back: vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); - if (vma && vma->vm_start < addr + len) { - if (do_munmap(mm, addr, len)) - return -ENOMEM; - goto munmap_back; + if (vma) { + if (unlikely(vma->vm_flags & VM_REVOKED)) + return -ENODEV; + if (vma->vm_start < addr + len) { + if (do_munmap(mm, addr, len)) + return -ENOMEM; + goto munmap_back; + } } /* Check against address space limit. */