From: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> commit 3ed4bb77156da0bc732847c8c9df92454c1fbeea upstream. When splitting a value entry, we may need to add the new nodes to the LRU list and remove the parent node from the LRU list. The WARN_ON checks in shadow_lru_isolate() catch this oversight. This bug was latent until we stopped splitting folios in shrink_page_list() with commit 820c4e2e6f51 ("mm/vmscan: Free non-shmem folios without splitting them"). That allows the creation of large shadow entries, and subsequently when trying to page in a small page, we will split the large shadow entry in __filemap_add_folio(). Fixes: 8fc75643c5e1 ("XArray: add xas_split") Reported-by: Hugh Dickins <hughd@xxxxxxxxxx> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/xarray.c | 2 ++ 1 file changed, 2 insertions(+) --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1080,6 +1080,7 @@ void xas_split(struct xa_state *xas, voi xa_mk_node(child)); if (xa_is_value(curr)) values--; + xas_update(xas, child); } else { unsigned int canon = offset - xas->xa_sibs; @@ -1094,6 +1095,7 @@ void xas_split(struct xa_state *xas, voi } while (offset-- > xas->xa_offset); node->nr_values += values; + xas_update(xas, node); } EXPORT_SYMBOL_GPL(xas_split); #endif Patches currently in stable-queue which might be from willy@xxxxxxxxxxxxx are queue-5.4/xarray-update-the-lru-list-in-xas_split.patch queue-5.4/xarray-fix-xas_create_range-when-multi-order-entry-present.patch queue-5.4/mm-invalidate-hwpoison-page-cache-page-in-fault-path.patch