[patch 09/31] mm: fix madvise infinine loop

Greg KH
2007-03-19T21:41:01Z

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-stable review patch. If anyone has any objections, please let us know.

------------------

From: Nick Piggin <npiggin@suse.de>

madvise(MADV_REMOVE) can go into an infinite loop or cause an oops if the
call covers a region from the start of a vma, and extending past that vma.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
mm/madvise.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -155,11 +155,14 @@ static long madvise_dontneed(struct vm_a
* Other filesystems return -ENOSYS.
*/
static long madvise_remove(struct vm_area_struct *vma,
+ struct vm_area_struct **prev,
unsigned long start, unsigned long end)
{
struct address_space *mapping;
loff_t offset, endoff;

+ *prev = vma;
+
if (vma->vm_flags & (VM_LOCKED|VM_NONLINEAR|VM_HUGETLB))
return -EINVAL;

@@ -199,7 +202,7 @@ madvise_vma(struct vm_area_struct *vma,
error = madvise_behavior(vma, prev, start, end, behavior);
break;
case MADV_REMOVE:
- error = madvise_remove(vma, start, end);
+ error = madvise_remove(vma, prev, start, end);
break;

case MADV_WILLNEED:

--