3.6-stable review patch. If anyone has any objections, please let me know.
------------------ From: Michal Hocko <[email protected]> commit 36e4f20af833d1ce196e6a4ade05dc26c44652d1 upstream. Commit 0c176d52b0b2 ("mm: hugetlb: fix pgoff computation when unmapping page from vma") fixed pgoff calculation but it has replaced it by vma_hugecache_offset() which is not approapriate for offsets used for vma_prio_tree_foreach() because that one expects index in page units rather than in huge_page_shift. Johannes said: : The resulting index may not be too big, but it can be too small: assume : hpage size of 2M and the address to unmap to be 0x200000. This is regular : page index 512 and hpage index 1. If you have a VMA that maps the file : only starting at the second huge page, that VMAs vm_pgoff will be 512 but : you ask for offset 1 and miss it even though it does map the page of : interest. hugetlb_cow() will try to unmap, miss the vma, and retry the : cow until the allocation succeeds or the skipped vma(s) go away. Signed-off-by: Michal Hocko <[email protected]> Acked-by: Hillf Danton <[email protected]> Cc: Mel Gorman <[email protected]> Cc: KAMEZAWA Hiroyuki <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: David Rientjes <[email protected]> Acked-by: Johannes Weiner <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/hugetlb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2481,7 +2481,8 @@ static int unmap_ref_private(struct mm_s * from page cache lookup which is in HPAGE_SIZE units. */ address = address & huge_page_mask(h); - pgoff = vma_hugecache_offset(h, vma, address); + pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + + vma->vm_pgoff; mapping = vma->vm_file->f_dentry->d_inode->i_mapping; /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
