4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Johannes Weiner <[email protected]> commit 59749e6ce53735d8b696763742225f126e94603f upstream. The radix tree counts valid entries in each tree node. Entries stored in the tree cannot be removed by simpling storing NULL in the slot or the internal counters will be off and the node never gets freed again. When collapsing a shmem page fails, restore the holes that were filled with radix_tree_insert() with a proper radix tree deletion. Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Johannes Weiner <[email protected]> Reported-by: Jan Kara <[email protected]> Acked-by: Kirill A. Shutemov <[email protected]> Reviewed-by: Jan Kara <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Matthew Wilcox <[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/khugepaged.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1525,9 +1525,11 @@ tree_unlocked: if (!page || iter.index < page->index) { if (!nr_none) break; - /* Put holes back where they were */ - radix_tree_replace_slot(slot, NULL); nr_none--; + /* Put holes back where they were */ + radix_tree_delete(&mapping->page_tree, + iter.index); + slot = radix_tree_iter_next(&iter); continue; }
