From 381636f33fe4af41fec076c5d9346a7369bcb40e Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 31 Mar 2022 08:27:09 -0400 Subject: [PATCH] XArray: Update the LRU list in xas_split() 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 Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Greg Kroah-Hartman --- lib/xarray.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/lib/xarray.c b/lib/xarray.c index 90e72b9f4b94..75da19a7a933 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1080,6 +1080,7 @@ void xas_split(struct xa_state *xas, void *entry, unsigned int order) 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, void *entry, unsigned int order) } while (offset-- > xas->xa_offset); node->nr_values += values; + xas_update(xas, node); } EXPORT_SYMBOL_GPL(xas_split); #endif