FAILED: patch "[PATCH] mm/huge_memory: initialise workingset state before folio" failed to apply to 6.18-stable tree

The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x aca1f2d5de17e138bc6c4859126b77e516b82541
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026081733-plastic-tidings-c30e@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From aca1f2d5de17e138bc6c4859126b77e516b82541 Mon Sep 17 00:00:00 2001
From: Matt Fleming <[email protected]>
Date: Sat, 25 Jul 2026 11:14:19 +0100
Subject: [PATCH] mm/huge_memory: initialise workingset state before folio
 split

xas_try_split() adds __GFP_ACCOUNT for page-cache xa_nodes, but
__folio_split() leaves the xa_state's xa_lru unset.  That lets a live,
memcg-charged xa_node exist without being linked into the mapping's
shadow_nodes list_lru; when reclaim later walks the list_lru it trips
VM_WARN_ON(!css_is_dying()).

Use mapping_set_update() to install both the workingset update callback
and the shadow_nodes list_lru on the xa_state.

Link: https://lore.kernel.org/[email protected]
Fixes: 58729c04cf10 ("mm/huge_memory: add buddy allocator like (non-uniform) folio_split()")
Signed-off-by: Matt Fleming <[email protected]>
Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=c5b060ce82921a2fd500
Reviewed-by: Zi Yan <[email protected]>
Acked-by: David Hildenbrand (Arm) <[email protected]>
Cc: Baolin Wang <[email protected]>
Cc: Barry Song <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Dev Jain <[email protected]>
Cc: Kairui Song <[email protected]>
Cc: Lance Yang <[email protected]>
Cc: Liam Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Nico Pache <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f84fe7913d88..5d94fa4c74fd 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -4076,7 +4076,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
 		gfp_t gfp;
 
 		mapping = folio->mapping;
-		min_order = mapping_min_folio_order(folio->mapping);
+		min_order = mapping_min_folio_order(mapping);
 		if (new_order < min_order) {
 			ret = -EINVAL;
 			goto out;
@@ -4090,6 +4090,8 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
 			goto out;
 		}
 
+		mapping_set_update(&xas, mapping);
+
 		if (split_type == SPLIT_TYPE_UNIFORM) {
 			xas_set_order(&xas, folio->index, new_order);
 			xas_split_alloc(&xas, folio, old_order, gfp);