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). Acked-by: Alan Cox Signed-off-by: Pekka Enberg Cc: Christoph Hellwig Signed-off-by: Andrew Morton --- include/linux/mm.h | 1 + mm/memory.c | 3 +++ mm/mmap.c | 12 ++++++++---- 3 files changed, 12 insertions(+), 4 deletions(-) diff -puN include/linux/mm.h~revoke-special-mmap-handling include/linux/mm.h --- a/include/linux/mm.h~revoke-special-mmap-handling +++ a/include/linux/mm.h @@ -168,6 +168,7 @@ extern unsigned int kobjsize(const void #define VM_MAPPED_COPY 0x01000000 /* T if mapped copy of data (nommu mmap) */ #define VM_INSERTPAGE 0x02000000 /* The vma has had "vm_insert_page()" done on it */ #define VM_ALWAYSDUMP 0x04000000 /* Always include in core dumps */ +#define VM_REVOKED 0x08000000 /* Mapping has been revoked */ #define VM_CAN_NONLINEAR 0x08000000 /* Has ->fault & does nonlinear pages */ diff -puN mm/memory.c~revoke-special-mmap-handling mm/memory.c --- a/mm/memory.c~revoke-special-mmap-handling +++ a/mm/memory.c @@ -2645,6 +2645,9 @@ 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) diff -puN mm/mmap.c~revoke-special-mmap-handling mm/mmap.c --- a/mm/mmap.c~revoke-special-mmap-handling +++ a/mm/mmap.c @@ -1080,10 +1080,14 @@ unsigned long mmap_region(struct file *f 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. */ _