Messages in this thread | | | Date | Fri, 11 Nov 2011 18:24:58 +0100 | From | Andrea Arcangeli <> | Subject | Re: [PATCH] mmap: fix loop when adjusting vma |
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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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