2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Mel Gorman commit a425a638c858fd10370b573bde81df3ba500e271 upstream. madvise(MADV_WILLNEED) forces page cache readahead on a range of memory backed by a file. The assumption is made that the page required is order-0 and "normal" page cache. On hugetlbfs, this assumption is not true and order-0 pages are allocated and inserted into the hugetlbfs page cache. This leaks hugetlbfs page reservations and can cause BUGs to trigger related to corrupted page tables. This patch causes MADV_WILLNEED to be ignored for hugetlbfs-backed regions. Signed-off-by: Mel Gorman Cc: stable@kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/madvise.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/mm/madvise.c +++ b/mm/madvise.c @@ -112,6 +112,14 @@ static long madvise_willneed(struct vm_a if (!file) return -EBADF; + /* + * Page cache readahead assumes page cache pages are order-0 which + * is not the case for hugetlbfs. Do not give a bad return value + * but ignore the advice. + */ + if (vma->vm_flags & VM_HUGETLB) + return 0; + if (file->f_mapping->a_ops->get_xip_mem) { /* no bad return value, but ignore advice */ return 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/