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    SubjectRe: [PATCH] mmap: fix loop when adjusting vma
    On Fri, Nov 11, 2011 at 08:53:23PM +0800, Hillf Danton wrote:
    > --- a/mm/mmap.c Fri Nov 11 20:35:46 2011
    > +++ b/mm/mmap.c Fri Nov 11 20:41:32 2011
    > @@ -490,6 +490,7 @@ __vma_unlink(struct mm_struct *mm, struc
    > int vma_adjust(struct vm_area_struct *vma, unsigned long start,
    > unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
    > {
    > + unsigned long saved_end = end;
    > struct mm_struct *mm = vma->vm_mm;
    > struct vm_area_struct *next = vma->vm_next;
    > struct vm_area_struct *importer = NULL;
    > @@ -634,7 +635,14 @@ again: remove_next = 1 + (end > next->
    > */
    > if (remove_next == 2) {
    > next = vma->vm_next;
    > - goto again;
    > + if (next) {
    > + /*
    > + * we have more work, reload @end in case
    > + * it is clobbered.
    > + */
    > + end = saved_end;
    > + goto again;
    > + }
    > }

    Doesn't matter if it's clobbered, remove_next will be set to 1 and
    that's all we care about. Caller should use vma->vm_next->vm_end as
    "end" anyway for case 6 so it wouldn't be set to 2. Also next can't be
    NULL if remove_next == 2. So I don't think this is necessary.


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