This patch renames VM_NODUMP into VM_DONTDUMP: this name matches to other
negative flags: VM_DONTEXPAND, VM_DONTCOPY. Currently this flag used only for
sys_madvise next patch will use it for replacing outdated flag VM_RESERVED.

Also this patch forbids madvise(MADV_DODUMP) for special kernel mappings
VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)

Signed-off-by: Konstantin Khlebnikov <khlebni...@openvz.org>
Cc: Jason Baron <jba...@redhat.com>
Cc: Nick Piggin <npig...@kernel.dk>
Cc: Hugh Dickins <hu...@google.com>
---
 fs/binfmt_elf.c    |    2 +-
 include/linux/mm.h |    2 +-
 mm/madvise.c       |    8 ++++++--
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 1b52956..3adcc4b 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1115,7 +1115,7 @@ static unsigned long vma_dump_size(struct vm_area_struct 
*vma,
        if (always_dump_vma(vma))
                goto whole;
 
-       if (vma->vm_flags & VM_NODUMP)
+       if (vma->vm_flags & VM_DONTDUMP)
                return 0;
 
        /* Hugetlb memory check */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ee2676e..21cad77 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -102,7 +102,7 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_HUGETLB     0x00400000      /* Huge TLB Page VM */
 #define VM_NONLINEAR   0x00800000      /* Is non-linear (remap_file_pages) */
 #define VM_ARCH_1      0x01000000      /* Architecture-specific flag */
-#define VM_NODUMP      0x04000000      /* Do not include in the core dump */
+#define VM_DONTDUMP    0x04000000      /* Do not include in the core dump */
 
 #define VM_MIXEDMAP    0x10000000      /* Can contain "struct page" and pure 
PFN pages */
 #define VM_HUGEPAGE    0x20000000      /* MADV_HUGEPAGE marked this vma */
diff --git a/mm/madvise.c b/mm/madvise.c
index 14d260f..03dfa5c 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -69,10 +69,14 @@ static long madvise_behavior(struct vm_area_struct * vma,
                new_flags &= ~VM_DONTCOPY;
                break;
        case MADV_DONTDUMP:
-               new_flags |= VM_NODUMP;
+               new_flags |= VM_DONTDUMP;
                break;
        case MADV_DODUMP:
-               new_flags &= ~VM_NODUMP;
+               if (new_flags & VM_SPECIAL) {
+                       error = -EINVAL;
+                       goto out;
+               }
+               new_flags &= ~VM_DONTDUMP;
                break;
        case MADV_MERGEABLE:
        case MADV_UNMERGEABLE:

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