mremap will create a 'duplicate' mapping if old_size == 0 is specified. Such duplicate mappings make no sense for private mappings. If duplication is attempted for a private mapping, mremap creates a separate private mapping unrelated to the original mapping and makes no modifications to the original. This is contrary to the purpose of mremap which should return a mapping which is in some way related to the original. Therefore, return EINVAL in the case where if an attempt is made to duplicate a private mapping. Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> --- mm/mremap.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/mremap.c b/mm/mremap.c index cd8a1b1..076f506 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -383,6 +383,13 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr, if (!vma || vma->vm_start > addr) return ERR_PTR(-EFAULT); + /* + * !old_len is a special case where a mapping is 'duplicated'. + * Do not allow this for private mappings. + */ + if (!old_len && !(vma->vm_flags & (VM_SHARED | VM_MAYSHARE))) + return ERR_PTR(-EINVAL); + if (is_vm_hugetlb_page(vma)) return ERR_PTR(-EINVAL); -- 2.7.5 -- 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>
