From: Michal Hocko Date: Mon, 8 Oct 2012 23:33:31 +0000 (-0700) Subject: hugetlb: do not use vma_hugecache_offset() for vma_prio_tree_foreach X-Git-Tag: v3.7-rc1~74^2~27 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=36e4f20af833;p=pandora-kernel.git hugetlb: do not use vma_hugecache_offset() for vma_prio_tree_foreach 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 Acked-by: Hillf Danton Cc: Mel Gorman Cc: KAMEZAWA Hiroyuki Cc: Andrea Arcangeli Cc: David Rientjes Acked-by: Johannes Weiner Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed