The patch titled
Subject: mm: kmem: fix split_page_memcg()
has been added to the -mm mm-unstable branch. Its filename is
mm-kmem-add-lockdep-assertion-to-obj_cgroup_memcg-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-kmem-add-lockdep-assertion-to-obj_cgroup_memcg-fix.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Subject: mm: kmem: fix split_page_memcg()
Date: Mon, 19 Aug 2024 16:04:15 +0800
split_page_memcg() does not care about the returned memcg for kmem
pages, so folio_memcg_charged() should be used, otherwise obj_cgroup_memcg
will complain about this.
Link: https://lkml.kernel.org/r/20240819080415.44964-1-songmuchun@xxxxxxxxxxxxx
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Reported-by: syzbot+ef4ecf7b6bdc4157bfa4@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://lkml.kernel.org/r/0000000000006f7e4d0620042b96@xxxxxxxxxx
Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/mm/memcontrol.c~mm-kmem-add-lockdep-assertion-to-obj_cgroup_memcg-fix
+++ a/mm/memcontrol.c
@@ -3035,12 +3035,11 @@ void __memcg_slab_free_hook(struct kmem_
void split_page_memcg(struct page *head, int old_order, int new_order)
{
struct folio *folio = page_folio(head);
- struct mem_cgroup *memcg = folio_memcg(folio);
int i;
unsigned int old_nr = 1 << old_order;
unsigned int new_nr = 1 << new_order;
- if (mem_cgroup_disabled() || !memcg)
+ if (mem_cgroup_disabled() || !folio_memcg_charged(folio))
return;
for (i = new_nr; i < old_nr; i += new_nr)
@@ -3049,7 +3048,7 @@ void split_page_memcg(struct page *head,
if (folio_memcg_kmem(folio))
obj_cgroup_get_many(__folio_objcg(folio), old_nr / new_nr - 1);
else
- css_get_many(&memcg->css, old_nr / new_nr - 1);
+ css_get_many(&folio_memcg(folio)->css, old_nr / new_nr - 1);
}
unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
_
Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are
mm-kmem-remove-mem_cgroup_from_obj.patch
mm-kmem-add-lockdep-assertion-to-obj_cgroup_memcg.patch
mm-kmem-add-lockdep-assertion-to-obj_cgroup_memcg-fix.patch
