From: Hugh Dickins Fix vma_adjust adjust_next wrapping: Rajesh V. pointed out that if end were 2GB or more beyond next->vm_start (on 32-bit), then next->vm_pgoff would have been negatively adjusted. Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton --- 25-akpm/mm/mmap.c | 27 +++++++++++++++++---------- 1 files changed, 17 insertions(+), 10 deletions(-) diff -puN mm/mmap.c~mm-vma_adjust-adjust_next-wrap mm/mmap.c --- 25/mm/mmap.c~mm-vma_adjust-adjust_next-wrap Wed Jun 2 15:12:24 2004 +++ 25-akpm/mm/mmap.c Wed Jun 2 15:12:25 2004 @@ -373,20 +373,27 @@ void vma_adjust(struct vm_area_struct *v if (next && !insert) { if (end >= next->vm_end) { + /* + * vma expands, overlapping all the next, and + * perhaps the one after too (mprotect case 6). + */ again: remove_next = 1 + (end > next->vm_end); end = next->vm_end; anon_vma = next->anon_vma; - } else if (end < vma->vm_end || end > next->vm_start) { + } else if (end > next->vm_start) { /* - * vma shrinks, and !insert tells it's not - * split_vma inserting another: so it must - * be mprotect shifting the boundary down. - * Or: * vma expands, overlapping part of the next: - * must be mprotect shifting the boundary up. + * mprotect case 5 shifting the boundary up. + */ + adjust_next = (end - next->vm_start) >> PAGE_SHIFT; + anon_vma = next->anon_vma; + } else if (end < vma->vm_end) { + /* + * vma shrinks, and !insert tells it's not + * split_vma inserting another: so it must be + * mprotect case 4 shifting the boundary down. */ - BUG_ON(vma->vm_end != next->vm_start); - adjust_next = end - next->vm_start; + adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT); anon_vma = next->anon_vma; } } @@ -418,8 +425,8 @@ again: remove_next = 1 + (end > next-> vma->vm_end = end; vma->vm_pgoff = pgoff; if (adjust_next) { - next->vm_start += adjust_next; - next->vm_pgoff += adjust_next >> PAGE_SHIFT; + next->vm_start += adjust_next << PAGE_SHIFT; + next->vm_pgoff += adjust_next; } if (root) { _